☛ The Java Problem, and what you should do
Good article there about how to disable Java, which you should do right now if you haven’t already.
I wrote a similar article for TUAW and also include a (Mac only) solution if you have to use Java on a “known safe” site. (TL;DR version: use Fluid.app.
Note #1: iPads and iPhones don’t have Java, so you don’t have to worry about those.