According to the BBC website story and a few other pages there is a serious security flaw within Microsoft's built-in Internet Explorer.
Now might be a good time to try the alternatives, especially Firefox (sometimes called Iceweasel). It's Open Source so you have the certainty of knowing that more than just one group of individuals have inspected the code and are looking for issues.
It's available for many platforms and easy to install, not to mention having many plug-ins to help you get what you want out of the web.