try following....
audacity
ddclip
trakadat
goldwave.com i believe has one.
tou can find a list at hitsquad.com under multitrack recording music software.
for a few bucks i highly recommend magix audio studio and powertracks. also n track.
hth
Oh, one other thing: You're supposed to either stop using N-Track, or pay for it, after a certain number of days; so it's not really "free". It's more like shareware. ProTools FREE, on the other hand, is truly free. I'm NOT saying it's better, mind you! But it could be better for some.