I would start with Audacity. IMO, you can't go wrong with free software.
Everything I transfer into Audacity is either already in digital format, or it's something that's already been laid out in analog and all that's required is a digital conversion. And in this sort of an application (basically using it as a mixer), Audacity always seems to work like a charm.
However, I have no experience doing multi-track recording with Audacity. In other words, I have never actually plugged an instrument or a microphone directly into the computer, and so I'm not sure how all that stuff works. I have essentially been using it as a mixer.
Joe