Internet service, whether wired or wireless, is constantly changing. Speed problems, DNS issues, lost packets, they're all happening constantly, and they're happening at every peering point between you and the streaming server. most of it has nothing to do with what's happening on your end of the circuit. Having to reset every hour or two is not uncommon, although I agree it's annoying.
The only real solution is to increase your cache (iTunes and most other players have settable cache sizes) or to stream at a lower bit rate so that the same size cache equals more music time. The reason players have caches is because of the variability of the stream; they play out of the cache when the stream chokes, and they hope the stream recovers before the cache runs out. Bigger cache = more allowance for variability.
If the stream you're listening to (such as Radio 66) is choking badly on the server side, there won't be much you can do. Bandwidth is expensive, and many Internet stations are shoestring operations.
David
