I have a waterproof bag for my Verizon Droid Incredible (I have included a link below). It says its waterproof up to 100 ft. If I take my phone scuba diving with me in that bag I’m sure the phone will stay dry however will the pressure of the water outside the bag cause damage to the phone? In case your wondering, I want to use the Camera functions of the phone not make calls under water. I also don’t exptect to dive below 60ft (I have already email the company, surprise…. they did not know.)

http://www.thepocketsolution.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=PS&Product_Code=PSI-63311&Category_Code=verizon_droid_incredible_accessories

It may not get wet nor damaged but the air in the bag will compress. It’ll probably cause that bag to activate all sorts of buttons on the phone during that compression as the bag contacts the phone. Some all at once. This commonly happens with cameras in those bags.
Your call here. Personally I wouldn’t since the results will be unpredictable. You can rent a camera from the charter or dive outfit you’re going with that will handle 60 feet for dirt cheap. You won’t also have a bag distorting your images. You only get one shot at this so why waste time, effort and money that may get you nada. Be a diver and do it right first time.