Water Warfare.
It's on WiiWare, and it's pretty solid for a WiiWare game.
It's not paintball, but it's pretty much what you said.

I own an Android phone and even though it got me really excited for the first couple weeks, soon I realized that it still has a long way to go. There's only one thing I find useful on Android and that is the ability to assign a specific application for a specific task. It really is nice but that's p...