A new build of Windows Phone 7 has leaked and this one is apparently the "RC1 escrow" build (as in "release candidate 1 escrow"), which means that if it passes certain quality criteria it will be declared the actual release candidate 1 build. If not, fixes will be made and the build will be incremented, and they’ll try again. (PocketNow apparently doesn’t understand the "escrow" language, which has been used at Microsoft for many years; they just believe it is the RC1 build.)
In any event, you can download an unlocked version of the RC1 escrow (build 6176) from XDA Developers and then use the instructions I linked to earlier in How to try Windows Phone 7 right now to get it up and running in emulation.
I’m doing this right now and will report back in a bit to make sure it works properly.
Update: Still downloading, but if I’m reading that build number right, the build is actually a month old already, so it’s pretty likely that Windows Phone 7 has indeed hit the release candidate stage.
Update: OK, it appears to work properly. No major differences that I can see quite yet, but it does appear to work OK.