As Senor123 said the only thing you really need to make sure of is that you go to the Ratcha Ferry Co wharf as the other is I think called Raja which takes about an extra hour and is a big old cluncker that doesnt have very much in the way of facilities. The Ratcha Ferry Co is the one to the left as you drive down to where the ferry peirs are everything is fairly orderly and goes quicky but you need to make sure you get there early in order to get on as the lines can get pretty long and we had to wait an extra hour until the next one came on the way back. I have the timetable and prices we paid last year so I can get you them but it is very very reasonable I think around 300 baht for two adults and the car, I will update when I find the documents.
