What are some good exercises to help flatten my abdomen after giving birth?

Many options.: I'm not a personal trainer, but finding a good cardio/aerobic exercise routine (jogging, spinning, etc.), lots of sit-ups, combined with a very healthy diet, is the best way to go. Try to have fun during the process, and best of luck!

Toning: For flatter abdomen eat healthy & get physically active. Calories burned > calories consumed. To tighten ab's: crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge & “bicycling” exercise on back. Engage in regular aerobic exercise (i.e. running, swimming, Nordic track, bicycling, kickboxing, walking, cross country skiing, hiking, etc.)