I painted tees and such in malls for years here in Memphis. I started off with a single action Binks Wren, but quickly bought a Paasche VL dual-action brush and have stayed with them ever since. They're not too expensive, and can do fine lines, or bigger spray areas. I've shot acrylics, house paint, liquid make-up, and more thru the one's I've had over the years. You can find them (and replacement parts- very important for airbrushes) at most art and hobby shops. Createx paints are good to use for a lot of different uses.
One thing most people don't do is get a decent compressor. Get one with a holding / resevoir tank. They can be the small 'pancake' kind, or the bigger belt driven ones, and are not that expensive if you shop around.
There're also some magazines out there such as Airbrush Action Magazine that can give you some good advice and tutorials.
You can see some of my airbrushed stuff at-
http://www.midsouthcartoonists.com
or
http://www.pencilneckstudios.com
Feel free to shoot me a pm or email if you have any other questions.
Lin