If you have any information or rumors on Magic 2011 (the next core set) post it here!
so far we know:
Magic 2011 Pre-Release date is July 10-11, 2010
Magic 2011 Release date is July 16, 2010
Magic 2011 Launch Parties on July 16-18, 2010
Magic 2011 Game Day: August 14, 2010
it's going to have 249 cards
Design team includes: Aaron Forsythe (lead), Doug Beyer, Mark Globus, Tom LaPille, Gregory Marques
Development team includes: Erik Lauer (lead), Dave Guskin, Tom LaPille, Kenneth Nagle
Standard now rotates only once each year, with the release of the October large set. So Magic 2011 will enter Standard on its release without knocking anything out, then Magic 2010 and Shards of Alara block will leave Standard with the release of "Lights." The Standard format between Magic 2011 and "Lights" will consist of Shards of Alara block, Zendikar block, Magic 2010, and Magic 2011. After the release of "Lights," it will consist of Zendikar Block, Magic 2011, and "Lights."
Extended rotates at the same time, but there's no core set that will rotate out this year. (Eighth Edition went with Onslaught; Ninth Edition will go with Kamigawa block on the release of "Shake.")
I got all information from wizards Magic 2011 announcement here:
Announcing Magic 2011 : Daily MTG : Magic: The Gathering