Internetworkers: http://www.ibiblio.org/internetworkers/

[Jim Allman <jim AT ibang.com>]

Here's an interesting thread with some suggestions about controlling 
the sender in Mail.app:
        http://www.macosxhints.com/article.php?story=20020507015639435

...and a simple explanation of the most direct method (still manual, 
but see the comments about ordering names):
        http://www.macosxhints.com/article.php?story=20010401111133239

Finally, MailEnhancer is a program that will (among other tricks) let 
you change your sig based on the current sending account:
        http://www.versiontracker.com/dyn/moreinfo/macosx/21431
        http://home.insightbb.com/~n9yty1/MailEnhancer/

  =jimA=