M-Audio fast track - what's it compatible with?

I run my guitar through an M-Audio Fast Track USB interface into Guitar Rig 3 and it's really convenient. Since I'm pretty sure the interface can't be used directly in Audacity and I can't for the life of my get GR3 to work as a plug-in, I record directly onto the Guitar Rig tape deck, export the files as WAV then paste them into Audacity for editing/lining up etc. Kind of a pain but it works. I want to use the interface for recording vocals as well. I have an Apex USB mic but it can't really handle any kind of volume. I tried running a "1/4 mic (which I used on an old multi-track I used to have - sounded decent) through Guitar Rig on a clean setting but it's really not sensitive at all, meaning I have to really give 'er to get vocals to record. This didn't surprise me because when using my guitar I noticed the same kind of thing happening. Which other programs is the M- Audio FT USB compatible with? Pro-tools isn't really an option for me, so I was just wondering if anyone knows of programs that I can use with this interface, similar to Guitar Rig but for vocals or just general recording.

Thanks!

FWIW I have not tried any sequencer that did not work with the M-Audio Fast Track.

Try Reaper.

http://www.reaper.fm/