I would suggest, also depending on how much PA (wattage/ohms/etc..live/home
studio)a simple thing like an Low cost Behringer,Allen and Heath,or any
mixer, with USB or FIREWIRE. Be sure to take into consideration simple
things, that can get overlooked, Phantom Power, grounding, wether or not you
need a power amp, Compressors eq. ( Hardware or software-Many of the smaller
portable mixers come with software, and the mixers themselves will have
effects, etc..).and On the same agreement with Marek: Outboard hardware
is-sometimes-less finicky, if you're going live,you want something that isn't
going to freeze, or anything. having the pots and knobs and faders also has
an asthetic to it, like playing any insturment, the differance between
playing FOR people and Creating For Yourself first and them second, can be a
pan here, a fader slide there, and can animate your music.