I still use Outlook at work because we have an Exchange server, but I'm using the Mac OS X Mail.app for my personal email addresses. I really enjoy the IMAP support, but I miss the Outlook Rules. Now yes, I could and actually do use Procmail on some of my personal accounts, but that's not available to my @mac.com address. This message, sent to the applescript-users mailing list, includes a couple of examples and some instructions from one of Mail's developers. There's also a reference to the help file being updated to include better instructions on how to use this feature.
Thanks to: [AppleScript Info]