Recently Skype released new version: 184.108.40.206. You will be requested to update your application during Skype startup. However, you can have serious problems with launching it on Windows 7 machines. When you will try to login, Skype will crash with the most common, Windows message: Skype has stopped working. Fortunately, it can be fixed rather easy. [Update: Skype problem on May 26, 2011, has a different cause. Check our new post.]
You have to turn off the compatibility mode with previous version of Windows on the Skype shortcut properties! When you launch it again, it will work like a charm.