I believe your body will get used to the extra fiber over time and then it shouldn't be as much of a problem. That said, I'd start in by eating black beans more then other kinds first (they produce the least amount of gas.)
If you cook your own beans, make sure you cook them in fresh water (drain the soaking water off then fill the pot again.) This is supposed to help with the gassiness.
I know it can be embarrassing in certain situations, but, hey, at least you know your colon works!
Also, drink lots of water! When you up your fiber intake it's really important to get enough water or you have other problems too.
I hope this helps! I love beans, they are so versatile.