Outdated browser?

One thing I always struggle with, is the hilarious great number of outdated browser and to inform the users about that they are using something which may be half a century old (One more IE6-user and I quit!).
Also when some code is implemented to check the browser version it must be kept up to date which sucks.
But hey, there is this wonderful website http://www.browser-update.org just implement their script and it informs the users with a little bar that their browser seems to be a little bit out of date.
Sweet tool.