Since you're obviously a beginner, you should go for a starter Digital SLR camera, a big upgrade from the Canon S3IS. A good entry-level digital SLR is the Canon eos XSI with an 18-55mm lens- It's Great!
It has a three inch screen, live view, Twelve megapixels, and a kit lens that features image Stabilization- a camera that any amateur would love. It'll get you started, here's a kit from amazon.com for a good price:
http://www.amazon.com/Canon-Digital-Camera-18-55mm-3-5-5-6/dp/B0012YA85A/ref=pd_bbs_sr_1?ie=UTF8&s=electronics&qid=1223222143&sr=8-1
That's a Bargain, lighting and additional lenses would set you back around one thousand more. Studio-like Photography isn't cheap. There's cheaper alternatives if you don't plan to be Professional.