Fedora 18 has been riddled by delays but developers are hoping to get a good hold on Fedora 19. Fedora 19 is codenamed Schrödinger's Cat and the hope is to have it arrive in May.
There's been a FESCo ticket the past few weeks for coming up with the Fedora 19 schedule. The general availability release date planned in the proposal was 21 May for the next release. This was discussed then at today's Fedora Engineering & Steering Committee meeting.
It was decided to have the F19 feature submission deadline at the end of January and to initially target for an end-of-May release with an end-of-February branch date. However, this may be pushed back depending upon the submitted features for Fedora 19. An official Fedora 19 schedule will be defined after the feature submission deadline.