Blizzard has plans to open two Public Test servers that will allow players to test the patches before they go live.  This is a feature many MMO veterans wished from Blizzard, since some of MMOs out there offer this feature.  The bad news is that some lvl 56-60 players will be chosen at random to allow them access to this Public Test servers.  Make sure to check your email often and make sure to check your Junk mail in case your provider has filters.  Read the full announcement Here.  To read the long patch notes for the new Public test servers go Here

Blizzard:
Two new public test realms will be going live soon! These realms will give select players the chance to experience new content before it is patched to public realms. More importantly, it gives us a place to test new features and systems in a live environment without impacting the public realms. This will allow us to provide players with more frequent content patches in the future.

Moving forward, all players who have an active World of Warcraft account will be eligible to participate in testing on the test realms. However, this initial testing phase requires characters between the levels of 55 and 60 in order to properly test the content and functionality for the next patch. Email invitations have been sent out to a random set of players who meet these qualifications. Their level 55 to 60 characters have been copied to the test realm and will be waiting for them when they log in for the first time.