It appears that there will be at least 2 more beta releases of Microsoft Windows AntiSpyware. The first one will be mainly to extend the beta-expiration date from July 31st to December 31st and will probably be released in the next few days (It has already been released to some testers).
The second update, Beta 2, will be released some time later this year containing some updates to the program.
For more details see Microsoft Set to Update Anti-Spyware Beta