Just a warning: I'm still using an outdated version of POPFile. Jutta uses a newer one, but not Mailsmith, rather Mail.app - anyway, you can easily combine the two scripts. The main difference is that my script looks for a colon and space and uses what comes after as a link, while Jutta's version uses the text between a < and a > as a link. If someone could just tell me how to do string manipulation properly in AppleScript, I could clean up the somewhat cumbersome source a bit - because at the moment I'm breaking the string down completely into individual characters and working through them. Somehow inelegant.
What was nice, however, was that porting from MailSmith to Mail.app only required minimal changes. These standard dictionaries of Mac programs are really a fine thing ...
Over at Der Schockwellenreiter you can find the original article.