Here are some of the stretches that I do on a regular basis to keep my back from getting too tight and sore. I hope they help you too! For more information go to p90x.iamcanadian.org
This is one of the best for my back and hips. It does make loud cracking noises in my spine however and you should do it every day… you should do all of them every day really.

Very simple stretch to help loosen up the back and abdominals

Very good for tight hamstrings that can cause all kinds of back problems

More advanced for hips, this is actually quite hard if you are male

Another very good stretch for hips and sciatic problems. You should feel the stretch in the buttock and hip of the leg that is crossed over, in this case the left leg.

Very basic, can be done in conjunction with an arching motion every time you stand up

A little more difficult for some, and also hard to control but once you can do it, it is very effective.

Be careful with this if you have pinched nerves, but the leg in front takes the load off the spine somewhat.

Cat stretch, also can be alternated with seal stretch where from the starting position you drop your hips to the floor and keep your arms straight.

Swiss army knife stretch, very good for hips and back

Basic and similar to the front bend, but this is a standing version of the cat stretch / seal stretch.