It’s a wonderful experience and I highly recommend it (I’ve already spent a summer there, otherwise I wouldn’t be saying “wonderful experience” just yet, lol). I’ve always been interested in studying French, but I never expected to actually study over there. But my unversity offered a summer exchange program at the University of Orléans and I spent three weeks there, fell in love with a French guy, and decided to go back for a year. Isn’t that how it happens?
It’s not too hard to get accepted to a French university for a semester or two. Everything will be done through your university – odds are yours will have a relationship with one or more universities in France, making it a bit simpler.
If you want something less involved (but still life-alteringly awesome) I’d definitely recommend a summer program. The one I attended in Orléans was great. There were students from 16 different countries, we were all friends pretty much instantly, and the teachers were good. No homework. We also went on a day trip to visit two castles and a wine cellar, with a free wine tasting. Also, the French students who were being paid (not nearly enough) to babysit us arranged different activities every single day. There’s a similiar program in Strasburg that sounds good as well, and for either of those you wouldn’t need a visa at all. Also, I got six credit hours and I think that’s pretty standard. Most universities offer at last $1000 scholarships for study abroad programs, so some aid is available.
That might be more of an answer than you wanted, but if not feel free to ask any questions you might have.
Good luck with your studies!