Sharepoint is a beast. Do yourself a favor and learn .net before trying to develop webparts for sharepoint. Learning both at the same time would be insanity at best.
However, you COULD learn the basics of sharepoint w/o developing anything. Lists, site admin, etc. You could do this basic stuff in parallel with learning .net then, when you are comfortable with .net you would probably be ready to digg into some sharepoint webparts--the real meat and potatoes of developing with sharepoint and .net.
there are a lot of cool things you can do with sharepoint and webparts, don't let the learning curve stop you. Get a couple of books and have at it.