Need HelpDesk program! Help!

[acidosmosis]

I work for an Internet service provider. We need a program that we can use to record information about customer's calls like what question they had, or billing problems or technical problems, and what we did to help them. Also possibly some kind of way to know which customers problems aren't resolved yet. Basically a sort of "open ticket" like Bellsouth uses.

If you know of anything even remotely near to this please let me know!!!