Sprint users!) Nexus S devices over the coming month, with the luckiest few to get it today. Outside of that, there's no more specific time table to be had, but if you're able to suck it down in the coming hours, definitely sound off on the improvements in comments below.
Update: Looks like the package is available to download and install (at your own risk, of course) for Nexus S, AWS version (T-Mobile compatible). Huzzah!