First, I pray. If I can't do that with the rest of the worship team, I'll pray as I warm up on some really familiar runs - just to get the blood flowin' to the digits. Then I'll tackle the runs or progression that we'll be doing in the songs for that set. Oh, yeah - I just found these great sites with some good stretches:
http://www.musicianshealth.com/stretches.htm
http://onhealth.com/home/interactives/healthieryou/basic/stretch007.asp

Hope this helps!