iOS 6 is finally available for public consumption and you can get it one of two ways: You can plug your iOS device in to your computer and check iTunes for an update, or you can go into the settings menu on your iPhone (3GS, 4 or 4S), iPod touch (4G, 5G) or iPad (iPad 2 or New iPad) and navigate to General > Software Update. And while updating shouldn't wipe out your previously stored data, you should back your device up just to be safe. And if you don't see the update popping up right away, just give it a minute. These things can sometimes take a while when first rolling out.
UPDATE: Cult of Mac dug up the direct links for each available build of iOS 6. They are as follows: