A good friend of mine, Mike Roberston, has a series of awesome products that feature mobility and how the lack of mobility is a serious problem to athletes, powerlifters and recreational lifters alike.
I've just recently made it a point to get back into the swing of doing it on a regular basis and I can honestly already start to feel a difference. I'm nowhere near where I was before, but it's getting better. My routine includes many of the exercises featured here in Mike and Eric Cressey's DVD Magnificent Mobility.
If you haven't seen it before, I highly suggest you check it out. If you aren't sure what kind of warm-ups you should be doing prior to or post workout, then, yes, you need to check it out. If you are sitting there saying, Ehh, I don't need that, then yes, you too, need to check it out. You won't regret it. Mobility, especially for athletes, is such an overlooked part of training, but it's so important and can really reduce the amount of injuries they have. It really is important. Do not leave this portion of your athletes' training out!