I have just flown my first seaplane, a Sig Fazer on floats. It is a .40-.46 size plane, 48" span weighing in the 5 pound range. I used Falcon Trading Co floats. With their adjustable mounting system, they were very easy to install. You slide the mount ot where you want it on a ridge on top of the float and screw them in place. My plane floats very high in the water. They come with a water rudder and a pull-pull set-up, but I made my own. Here is their URL and a couple more.

http://www.falcon-trading.com/product.cfm?prodID=8

http://www.geocities.com/planefunfloats/

http://www.foamcorefloats.com/

You'll enjoy float flying, it's a lot of fun and a new experience. I found you have to be aggressive with taxiing. My plane was so high the rear end of the floats and the water rudder were out of the water. I ended up using full up elevator and a good bit of power to keep the rudder in the water to steer during taxi.