No you can get a red Bumper for your iPhone and do good.
Apple has just released a new iPhone 4 bumper for the iPhone 4 and iPhone 4S. The new red (PRODUCT) RED bumper slips around the edge of your iPhone. With metal buttons for volume and power, two-tone colors, and a combination of rubber and molded plastic, Bumpers add protection and style to any iPhone 4S or iPhone 4.
The Product RED bumper is yet another product in the Apple product line-up supporting Bono's Global Fund that fights AIDS. Get the new Bumper on the Apple Store for $29 (Same price as other Bumpers).
If the new Bumper will fit the new iPhone 5 when comes out is unlikely. iPhone 5 bumpers are expected to be slimmer.