Red Hat engineers and the Fedora community have fixes for some bugs blocking Fedora 13 Alpha, but they need additional time to verify the issues as being resolved. Fortunately, as of right now, Red Hat is not pushing back the final release of Fedora 13 that is due out in the middle of May. There is also a beta release still due out at the start of April and a release candidate at the end of April.
Once released, Fedora 13 should be quite interesting with open-source NVIDIA 3D graphics support via the Nouveau OpenGL driver in Gallium3D (we have already benchmarked the Nouveau Gallium3D driver) for the recent GeForce generations and then a classic Mesa for NVIDIA's very old hardware. The Nouveau 3D support is just one of the many interesting features with other new features including Btrfs system roll-back support, KDE and Sugar updates, X Server 1.8 and other new X.Org features, DisplayPort and NFSv4, and other new packages.
The announcement of Fedora 13 Alpha being pushed back by a week can be read on the Fedora mailing list. The revised Fedora 13 schedule is available on the Fedora Project Wiki.