Hi Aly
Yes, there are hundreds of publishers...although lots of them won't publish the kind of book you're planning to write.
I know it probably sounds very basic, but one of the first things I'd do is head for the largest book shop near me and just see what's on the shelves, making a note of any that seem to publish the kind of material you're aiming to produce. This should save you a lot of time in the long run as, when you do get around to sending your synopsis to people, you will be targetting a potentially interested publisher (fingers crossed!)
Oh, and of course publishers' websites and various publications (eg The Writers and Artists Handbook) will also provide information about who produces what kind of material.
Good luck!
Caroline