The Jet Set Radio update will be released starting September 11, when the PS3 version will be available for PlayStation Plus users. The wider PS3 network release will occur September 18, for $9.99.
The XBLA and Steam versions will follow on September 19 for the same price. The Vita version will arrive October 16, which is officially not "summer" as originally announced. The console and PC versions can just barely claim a summer release, but October is past the equinox. We're not upset – just wanted to point out that we're onto you, Sega.