audio interface

I own a g4 mac with osX.
I use the built in minijack to record the sounds into my computer but I'm quite desapinted by the quality I get (what's quite expectable!). Could somebody tell me what kind of device i'd need to record high quality sound (USB or Firewire), and a good sound program. (I now use "soundtrack" but it's way less efficient than pro tools and pro tools doesn't work on osX.)

Pro Tools LE 6.1 does work for OSX. For the USB or firewire interfaces you can get an MBox or Digi 002. If you have a PCI slot available you can use Digi 001.

Thanx man!