
Version 3.1 and above of Pegasus Mail is IMAP compliant, in addition to POP. This makes it the best free e-mail client for Windows. Pegasus Mail also runs in DOS, Macintosh and Netware, but not Linux. You can have multiple accounts, filter mail, use spell checking, etc. You can download it free directly from its Website. If you want more information than provided in this tutorial or in Pegasus Mail help files you can also buy printed manuals for it. It has versions for twelve languages at the time of this writing.
The following image was taken from a session of Pegasus Mail in my machine. At the top you see Pegasus toolbar. At the left my folders in the UBMail server. In the right you see first my INBOX (new mail folder) in UBMail, followed by an open message, at the bottom.

You can file a message by dragging it from an open folder and dropping it in one of the folders at left. Of course, you can read, reply, forward, copy, delete, etc, by using the folder toolbar shown in the top of the right side. In the message window, shown in the bottom right side, you can also reply, forward, delete, print, etc. Finally, you can have many folders and messages open at the same time, allowing you to copy and paste between them.
After you download it, just double-click in the distribution file and the installation wizard will take you through the basics. Select a directory where to install Pegasus, select if you want one user (if only you use your machine) or many users (if many people uses your machine) to use Pegasus in your machine, select a user name to your Pegasus profile, enter your e-mail account, your POP (if you are going to use POP instead of IMAP, otherwise leave it blank) and SMTP (outgoing mail) servers. When this is done Pegasus installs itself an opens your first session.
From the Pegasus toolbar, select Tools, IMAP profiles. You will be placed in a window like the one shown here. In the example I have already created two profiles (I have two different e-mail accounts in IMAP servers). In the first time this window will not have any IMAP profiles. You will need to click on New to create your first (or only) profile. Once you create a profile, you can double-click on it to connect to the IMAP server and access your folders. Of course, you can edit or delete this profile after it is created. The image below show the dialog after you click New or Edit:

You start by giving a name to the profile (in our example was ubmail), then enter the IMAP server name, your username and password (password is not required and for security reasons you may omit). The other settings shown in the example (which work with UBMail) will depend of your server and if you want to open connection to the server at startup.
Pegasus let you customize receiving, sending, editting, etc, features. In order to do so select Tools, Options and you will see a new dialog as shown below:
As you can see there are twelve windows (tabs) allowing you to customize a variety of aspects of your e-mail setup.
In the General window you can enter your name as it will show in the from area of the header of your message like in "John Doe" <jdoe@mail.edu>. You should also enter the name of the folders where copies of your messages will be store, in our example SENTMAIL. Also enter the name of the folders where messages which were read and not moved to a specific folder will be saved, in our example MAIL. The two names used in the example for these folder provide compatibility with other older e-mail clients, and I suggest you to use them.
The other general settings will depend on your preferences. You can delete your messages immediately or keep them in a special folder until you end your session, allowing you to recover from mistakes when deleting messages, or not. You may decide if you keep messages you read in the new folder (as read) or if you wish the messages moved automatically to saved mail folder (MAIL in our example).
You can also decide to have the ability to choose how to send your message at the time you are replying to messages. Most probably you will wish to maintain your desktop selections from one session to another. Finally, if you tend to send long messages you will wish to set a time in minutes to save your messages in progress to avoid losing them if a machine failure happens.
You may also wish to customize Message and Hyperlinks settings. In the Message Window be sure that MIME is selected, since it is the standard Internet attachment protocol. In the Hyperlinks Window you should enable the display of clickable links in the messages, and you may let Pegasus look for your default browser or you may indicate the browser you want to use.
Filtering is a savior when you don't want to read messages sent from somebody which constantly send you "junk mail." It is also very useful to automatically move messages from mailing lists to their respective folders to decrease the clutter in your INBOX. It also can be used to move messages on a subject to a given folder, as in the case of student assignments if they use as a subject a topic you predefined. You can also move automatically messages from your frequent correspondents to their own folders. In the first case you want to delete automatically the junk mail messages. In the cases of mailing lists and student assignments you want to move the messages to their respective folders, and open the folders periodically and read the new messages. In the case of your active correspondents you want to copy the messages to their respective folders, and read, reply, delete the messages as they come in, since you already have an archival copy of the messages.
The way you set filtering in your INBOX (or any other) folder is creating rules of what Pegasus should do when you open the folder. Start by defining rule-sets: Select Tools, Mail Filtering rules, Create/edit general rule set. You will see a dialog shown in this image. In the example I have two rule sets: courses and lists, but in the first time no rule set will exist. Click on New to create a new rule set. It will ask you for a name of the rule set: choose a name that has meaning for your like courses mean to me the rules to filter student assignments to their mailboxes. This is an example of a rule in my courses rule set. It simply says "if 610A1 is found in the subject field of a message, then the message should be moved to the folder 610A1." As you also can see in this other image I created a variety of rules for my courses rule set.
The final step to setup filtering is to assign the rule set you wish to a given folder. Right-click on the folder you want to apply the rule set to and select Attach folder-open filter set. A dialog for rule sets will be shown and will let you select the rule set to apply. To remove the rule set from a folder right-click on the folder and select Detach filter sets from entry.
Note: I personally do not attach rule sets to my folders, for I like to see all the messages which come in, and also allows faster loading of the folder. After I take a look at the message headers, I select Tools, Mail filtering rules, Apply general rule set to folder and select what rule set to use. This is specially useful when the IMAP server is slow.