wakeskating.com has some message boards that would be a great resource. But board size in wakeskating is much more up to preference than wakeboarding, so anything around 40 or smaller would be fine for anyone to use. Also, material can be left up to preference as well, as you will find some people prefer the weight of wood and others will prefer lighter materials. As far as where to get them from, that's a more complicated issue. A general rule of thumb is to stay away from the major companies (Liquid Force, Hyperlite, etc) as the boards may not seal properly and delam, and won't last you nearly as long. The best boards that will last you the longest are made independently, so manufacturing is usually seasonal and the scene changes regularly. The best companies to look at are New, Integrity, Remote, and Oak, among others. It can be difficult to find them, but the service and quality goes above and beyond others.
Here would be some great skates to start out on:
Cheap, and they'll last you a long time. And granted that you are gonna want grip tape on your skate, you need to pick up shoes. Anything light will work, you don't need to buy actual wakeskate shoes. I started out using cheap faded glories from walmart, cost about $5 and they don't hold too much water. Let me know if you have any other questions, the feeling after riding on a skate and having freedom to move is like nothing else. I have a tough time getting everyone I take out to get on the wakeboard, but I've never had a person turn down the wakeskate. Good luck.
Also, the forums at wakeskating.com are a great resource too if you wanna do some further searching and research.