Squats, lunges and bench dips are great body resistant exercises. You definitely don't need weight when you're first starting out. There are also lots of different variations on the types of squats and lunges you can do. It's very important to make sure you have proper form though to avoid injury. Sometimes you can find videos of the proper techniques on youtube. I'd suggest starting with static lunges and a basic squat and then progressing from there into more dynamic movements.
The plank is also fantastic for toning your arms/core.
Edit: And I just realized I pretty much said verbatim what CandyKisses said...
Great minds think alike!