Is anyone aware of any sites with good Star Wars concept art, preferably front and side shots? I'm curious because I'm intending to follow a tutorial (hopefully to improve my modeling abilities), but have been unable to locate any quality Star Wars concept art.

well - I'm a concept artist.

If anyon has anything specific tell me - and I want it to be somewhat specific :)

Look up the Art of Star Wars books and Ralph MacQuarrie stuff.

Im not sure, but sometimes SW fansites have some art so try looking into those.

That Ralph MacQuarrie site I found is awesome. He has some great work.