Swim bladder disease wasn't really something I knew a lot about so I went to read about it.
It seems as though it looks worse than it is and is not often fatal. Not contagious but it could indicate an underlying problem with your tank (water problems, overfeeding + many more)
Seems as though there are a few causes and the most common suggestion to cure it is to avoid feeding for 3 days then feed with a mushed up defrosted shelled pea.
(aparently the illness is often caused by a blockage in the intestinal tract if not by a bacterial infection)
Frequent and large water changes are a good idea and keep an eye on your water parameters.
I found this interesting, yet relatively short article on Wiki about the swim bladder (they say Gas bladder) It wont help cure the problem but it's quite interesting if yuor into that kinda stuff. (theres a pic of a swim bladder)
Check it out:
http://en.wikipedia.org/wiki/Swim_bladder