Suggestions for SL-based bug tracker

A developer (of a line of Windows products) I know is abandoning his
Yahoo-groups forums for good reasons, and moving to a web-based "Help
Desk" package that sounds ghastly---can't post to it via email, for
one thing.  He thinks it'll make life better for him, by assigning
tracking numbers and organizing the threads that his largely-clueless
customers seem incapable of doing on their own.  Some of the current
beta testers are howling in protest, wanting to keep an email
capability, and some are even advocating his moving to my provider's
site that hosts secure SmartList lists economically.  (A lot of the
beta testers subscribe to a related list that I maintain.)

If I were in his position, I'd want to use SmartList in conjunction
with whatever additiions made sense to impliment a system for
providing help and tracking feedback from beta testers.  So, my
question to this esteemed group is, what do you know of that's off
the shelf that I could suggest to this guy?

The basic requirements seem to be some means of assigning ticket
numbers to bugs, or individual product support issues, and a searchable
archive, in addition to the usual mailing-list features.

He's probably hopelessly wedded to his help-desk web thingie, but it
seems worth at least pointing him to something more user friendly if
I can. 

TIA,

Jim