I want to find some yoga exercises that with stretch or exercise my stomach muscles. any ideas?
Here are some poses I would recommend looking at:
Cat-Cow Stretch
Plank Pose
Side Plank Pose - Vasisthasana
Twisting Prayer Lunge
Chair Pose - Utkatasana
Cobra pose transition to Up dog
Eagle Pose - Garudasana
Boat Pose - Navasana
Hope that is what you were looking for
OOPS-I had forgotten to put the links up for you so here they are:
http://www.yogajournal.com/
http://www.hathayogalesson.com/
http://www.santosha.com/asanas/