Sony Computer Entertainment Europe have released a Press Release detailing the release of Ratchet & Clank: Quest for Booty.
As part of the release, it says "This bite-sized treasure tale will be released this summer on PLAYSTATION®Network and Blu-ray Disc (BD)."
Also, it says "Ratchet and Clank: Quest for Booty contains up to four hours of action-packed gameplay."
The press release finishes confirming it's Summer 2008 release.