WH announces P.T. presser on Twitterhttp://firstread.msnbc.msn.com/archive/2009/07/17/2000333.aspx From NBC's Athena Jones Move over Facebook. The White House has crossed a new media frontier with Twitter, the latest Internet phenomenon.If you were a so-called "follower" of the Obama administration on Twitter, here's the message youen-USCommunityServer 2.0 (Build: 60608.1)