Ray, thanks for the warning. I fish rocks/ledges quite a bit up in Maine, so I'm well aware of the safety issues involved, especially when the surf kicks up like it has this week. I haven't been swimming yet, but I got bowled over by a rogue wave in Rye, NH last fall- That's a lesson I only needed to learn once.
Ed, as I'm sure you know the Korker brand cleats are pretty expensive(~$60), but I've made due in a pinch with the cheapo rubber 'ice cleats' you can find at wal-mart, etc. They're usually with the ice fishing stuff, so I don't know if you'll have much luck in the summer, but it might be worth a look. The drawback to these is that they generally only have cleats under the ball of the foot- great for walking on flat ice, not so good for scrambling across slimy rocks.