A bit late but I just found this topic...
To get a motorboat licence you will need to first pass a theory exam then pass a practical exam on the lake.
The theory exam is 60 questions and the pass rate is 56. You can learn the theory from the free handbooks given out by the SCAN or better still buy the interactive CD for Fr 79.00 (see
here). I don't think you can do the exam in English, but ask the SCAN (maybe they changed the rules).
Next, the practical exam must be taken within 18 months of getting the theory (otherwise you have to do the theory again!).
My advice: Take private lessons so you get 100% of the time in charge of the boat. Private lessons are around Fr 90 / hour and you are going to need at least 10 lessons.
Finally,
here's a list of all recognised instructors around Neuchatel. I recommend Philippe Marc Martin at Nid du Crô, he taught me and is a fun guy.
Good luck!