At this year’s Gamescom press conference, we announced that Online Game Save Storage will be upgraded to 1GB for PlayStation Plus members, and I’m happy to report that the increase will be available soon with PS3 system software update (v4.25)!
After you’ve installed the update, simply go to the Saved Data Utility under the Game column of the XMB. From there you can access the Online Storage folder and find any existing game saves already uploaded, as well as the increase in space to 1GB. So set your automatic download to upload every game save for every compatible game you play and enjoy the additional breathing room. You can also continue to use this feature to selectively upload game saves you specify.
This update should be hitting the evening of Sept 11.