I got a small Timbuk2 phone wallet ~ zips half-open to get phone in/out, one clear vinyl face so phone is still somewhat usable inside if you don't wanna go through the bother of taking it out, and has a couple small slots on the back side for ID, emergency cash/bank card, etc. Still small enough to slip in a jersey pocket. It's not waterproof but resistant enough to light rain/sweat, and also provides a little scuff protection against keys or tools if they're tossed in a bag together (though not any heavy padding if I were to crash land on it).