I keep mine in a Camelbak phone holster, ironically on my Hydrapak.

Two reasons, I have different rings for different folks. If my boss calls while I'm out on a ride off of business hours, it's an emergency. If that hot little brunette from the bar last weekend calls, you bet your ass I'm taking the call.

If it's just a friend or someone I don't care to hear from, F 'em. Also, my day is pretty packed so my riding time is usually overlapped with making plans for the evening etc. I can't hear it ring in my jersey pocket, but in a shoulder holster I can decide if it's worth checking or not.

And if it's a picture message from that same hot little brunette... yeah, I'm going to have to check that.

Damn you crackberry.