I don't think it was ever one a quarter, more like once every six months.

There is more or less a feature freeze on right now, concerning the release of 5.8.8. Nicholas Clark, the current maint pumpking posted plans a while back, indicating that he was hoping for an October release.

A week or so ago, he posted a message saying that he had Real $Work to do, which was going to occupy him up until the end of November. So with a bit of luck, there might be a release in December.

Keep an eye on the weekly p5p summaries, available on dev.perl.org and use.perl.org. All news concerning the Release Candidate series and the betas will no doubt appear therein.