My 3-year-old is very disruptive of other children's play. How do I help her respect other people's personal space and boundaries? Telling her not to do something makes her very angry. Also, she seems to have a lot of anger within.

With kids who are disruptive, working on empathy can be very helpful--not telling her what to do, but helping her learn to identify what others are feeling (which can lead to changes in behavior).

It is also good to keep in mind--especially if it runs in the family--that if ADHD shows up at that age, the most common symptoms are the ones you have described. It may be worth an evaluation by her pediatrician.