I took a turbocad class in highschool and an autocad class in college. Now I have solidworks and i never use anything else. if you have a little time on your hands you can teach yourself. i am entirely self taught and i have done some pretty involved models. as mentioned earlier the tutorials on solidworks are excellent and they really teach you how to use the program. i am sure you would learn a lot in a class but it would be hard for me to justify the cost after seeing how easy it is to learn.

Matt