As noted by 9to5mac, Apple just seeded Mac OS X 10.6.6 (build 10J521) to registered Mac developers. 10.6.6, another version of Snow Leopard -- we thought the upcoming 10.6.5 would be the last before Lion.
The only information provided in the changelog:
- Contains developer support for fetching and renewing App Store receipts. See “Validating App Store Receipts” for more details.
The release of a first 10.6.6 seed means the 10.6.5 version we've been talking about for months could be coming later today, tomorrow -- any day. It's ready, just waiting to be released publicly.