If you are talking about chest/abs/shoulders. You can do simple workouts such as modified crunches and push ups for looks. Also shoulder work outs are pretty easy and usually get very nice returns if you are consistent with it. I am really only about practical muscles though, not really into show unless it is for a Halloween costume. I think I might do Sagat this year, so I need to work on those superficial muscles.
I played basketball since I could walk really, could of played college BBall but decided not to. Rather have a life than wake up every morning to go to practice and sleep all through classes.
If you want to get into swimming as a supplement to running you can take the advice of the swimming in my favorite book:
Amazon.com: Runner's World Run Less, Run Faster: Become a Faster, Stronger Runner with the Revolutionary FIRST Training Program (Runners World): Bill Pierce, Scott Murr, Ray Moss: Books
Or if you are in college or near a Y or something, take some classes. I took a college course called Fitness Swimming and it was 1 hour course and learned a lot from it. Proper form helps a whole lot. Also if you are serious about swimming, get some jumper speedos and a nice pair of goggles. My recommendation would be Vanquisher's, you can find them at most sports stores.