Until now, it was said by Blizzard Entertainment that the StarCraft II Beta would close on Monday, May 31st, until the eventual re-opening until the title's actual release on July 27th. Blizzard blue poster Nethaera has now corrected their previous statement by clarifying that the beta will receive an extra week of availability. The new date, Monday, June 7th, will be extended for all testing regions.

Statement from Nethaera:

"We previously announced that the first phase of the StarCraft II beta test would be coming to a close in all regions on Monday, May 31. In order to prepare for the final phase of beta testing, we plan to extend the current phase in all regions until Monday, June 7. After this date, the beta test will be unavailable for several weeks while we make some hardware and software configuration changes for the final phase of the beta test and the release of the game. We plan to bring the beta test back online for a couple of weeks prior to the game's launch to complete our testing. We'll have more details to share about when this final phase will begin at a later date.

We'd like to thank all of our beta-test participants for your enthusiasm, dedication, and valuable feedback during the beta test, and we look forward to hearing more of your thoughts on the StarCraft II beta test as the game's July 27 launch approaches."

Source: Battle.net forums