Today the first Service Pack for Windows 7 is being released. If you are running Windows 7, head over to your Windows Updates and check for updates. The service pack is a few hundred megs, so depending on your connection, it might take a while. You will also have to restart during the installation process, so be expecting that.
I just updated to SP1, and there aren’t any obvious differences, just some bug fixes (although I didn’t notice any major bugs anyway).