Ok, so someone else may already have discovered this site, but I just did and thought it was worth sharing. It's from Matt Kosklowsi who is one of the Kelby Training gurus and their Lightroom specialist. The site includes videos of Lightroom features but also has some FREE presets to download and install to your own LR4 (or LR3 - note these presets are not the same so don't get confused). Enjoy!

http://lightroomkillertips.com