First though, with the GNOME 2.28 release schedule, its first unstable release (v2.27.1) will be out later this month on the 29th. For the next few months will be several more development releases in the GNOME 2.27 series and also minor bug-fix releases in the 2.26 series. Come this September, GNOME 2.28.0 is planned for release on the 23rd. Among many other features and changes to come, GNOME 2.28 will complete the migration from Mozilla/XulRunner to WebKit for its web rendering engine.
A month after the release of GNOME 2.28 will be the first GNOME 2.30 (3.0) development build and that will continue on in the usual GNOME development fashion until March of 2010. GTK 3.0 and Glib 3.0 are scheduled for release on the 22nd of February in 2010 while GNOME 3.0 is scheduled to be out on the 31st of March. In other words, we are just shy of being one year out from GNOME 3.0!
Landing in late August during the GNOME 2.28 development cycle will be the gnome-shell beta release. Throughout the GNOME 3.0 development cycle, various libraries will be stripped away such as libgnomeui, libglade, etc. The feature freeze for GNOME 3.0 will go into effect in late January.
The release schedule for GNOME 2.28 and GNOME 3.0 can be found on their GNOME Live web-site. Additionally, new details regarding GNOME 3.0 were also published today. From the revamping of the GNOME user desktop experience to streamlining of the platform to the promotion of the GNOME desktop, those details can be read about in detail here.