I agree with TAVS... just hang out, show her you like her, but don't tell her until you get a better read on her. Little things like body language, lots of smiling, maybe touching her arm while you talk, etc. Just ask her if she wants to go see a movie, don't make it seem like a big deal.

Go with the flow, and pay close attention to her reactions to your flirting. When the time comes you feel you know she's really digging you, try taking it a step further. Most important thing is to just be yourself, talk about whatever. Find out what she's interested in, ask her more about herself, girls love talking about themselves, but more important than that - they love when guys LISTEN, like - really listen and not just nod and smile while thinkin about what you would like to do to her ;p