Roland UA-30 USB audio interface.
This was the only USB audio interface I could find that works with my Powerbook running OS9. It's not that great, it clicks a lot during playback and you have to get exactly the right update of the OS with the right multimedia update from Apple to make it work. I tend to use the DAC in the Tascam DAT machine and go from there to the digital input on the UA-30 because I think the DAC is better on the Tascam. Anyway it works perfectly well for stereo recording.
Harmony Central reviews here