Here are some stretches/yoga poses that I have found to be beneficial for my pelvic pain. With all of them, remember easy does it. Don't feel like you have to force yourself as deep into the poses. Only go as far as it feels comfortable (i.e. if you're thinking "I really wanna get out of this" then you're in too deep- back off some). It's also helpful to hold them for a longer period of time (one minute would be good). And, naturally, do both sides.
A good variety
Supported child's pose
Lumbar rotation (gentle rocking back and forth with your breath)
Crossing and holding onto the ankles really helps to release
Good hip stretch- don't pull in too hard, just enough to feel some release (you can also prop your foot against a wall)
Thread the needle
Hamstring stretch (use a yoga strap, belt, etc)
Seated one legged stretch
Seated side stretch (you can also prop your forearm on a yoga block)
Supported garland pose
Happy baby pose
Supported reclined cobbler's pose (good for the pelvic floor muscles)
Child's pose (I really like it so it's in here several times!)
Meditation
Savasana and progressive muscle relaxation (look up free guides online)
For a video, this one is helpful for a gentle vinyasa type yoga:
For those a little more advanced, here are some hip opening poses shared with me: http://www.elephantjournal.com/2013/02/10-hip-opening-poses-to-awaken-your-root-and-sacral-chakras-kristen-coyle/