If you have sailed mono-hulls, then speed control is exactly the same. Unless you are in more extreme winds, speed is totally under your control via a combination of helm and sheeting in/out.
Aside from some nuances, your only 'big' learning curve will be when you try to tack the first few times. You need a bit of speed built up to make it easier and you can't just throw the rudder hard over. It has to be done gracefully or the double hulls will dig in and come to a halt as they don't like to turn sharp.
I highly recommend picking up a book on cat sailing or racing. Like you I expect, I considered my self a pretty decent small craft sailor but bought a book on cats when I got mine and I found a lot of useful tips in it. I think it made the transition a lot smoother.
I have http://www.amazon.ca/Catamaran-Sailing-CATAMARAN-Apr-17-1999-Paperback/dp/039331880X/ref=sr_1_2?s=books&ie=UTF8&qid=1397148597&sr=1-2&keywords=catamaran+sailing
by Phil Berman
The old style pictures in it leave a lot to be desired but the content is still very much relevant. My wife pretty much learned how to sail by reading it and practicing last year. I stayed as silent as I could unless she asked a question so as to avoid "the look" if I tried to give unsolicited advice but once she understood how the wind works in a sail from the book, she got the feel of things very quickly.
I have very little to offer the experts on this board, so I try to be slightly helpful by chiming in on these easier ones. However, the experts will likely have more to add as well.