hey hiddenlake, welcome to the site. the radios that we use to talk to each other are the FRS type walkie talkie/2-way radios. They go from cheap to not quite pricey. Case in point, I got my motorola T5420 for 10 bucks on sale, and it works really well. There are many other companies that make them as well, Uniden, Panasonic, Bell South, Cobra, etc. etc. etc. I've always stuck with motorola though (i figure since my phone is pretty indestructable they must make some decent radios).
There is both a channel and a subchannel (or privacy code) available on most of the radios. Since not all of them have this feature, we use channel 7 code 0 since this will work with ones that don't have the feature, just channel 7.
I'll see ya or talk to ya on the lake sometime.
steve