Here a simple one that displays the sender's E-mail address and Subject for unread e-mails for Gmail. You just have to replace wherever you see username:password with YOURusername:YOURpassword. This must be done twice in the code.
I snagged the initial parsing code from this geeklet:
http://www.macosxtips.co.uk/geeklets/internet/gmail-unread-title-and-summary/
