Anything that advertises "Mil-Std 810F" (or "Military Standard 810F") should be fine.

I know that some Motorola Nextel phones feature this. I use Nextel, so I looked this up a while ago. However, Sprint has purchased Nextel, and the "Nextel" service is supposed to eventually go away, so these phones will eventually be phased out.

I suspect that the other carriers offer ruggedized phones, too. But at least now you know what to look for. Don't forget to get something with long battery life too.

** Edit ** The MIL-STD-810 is an entire family of standards. I do not know what the "F" actually stands for. It is possible that you might see another letter besides "F". You will have to do some research to determine if it meets your needs.

Also, somebody mentioned a 2M Ham rig. If you get a tech license (very easy to pass, no morse code), Yaesu makes a waterproof HT that transmits on four bands, and has a metal case. You can probably run it through the dishwasher if it gets too dirty (OK. I wouldn't do that to a $300 radio, but you get the idea).