New developments in LTS
Historically, Edubuntu releases weren't released as long-term support releases with their Ubuntu LTS counterparts. While the Ubuntu LTS release was supported for 3 years on the desktop and 5 years on the server, the Edubuntu release was supported for the standard 18 months.
Ubuntu 12.04 takes a huge leap forward by not only supporting the server for 5 years, but also the desktop install. Derivatives can also separately apply for LTS status.
Some necessary changes
The Edubuntu team decided to apply for LTS status for 12.04, and had to made some changes in order to support Edubuntu 12.04 for such a period. The most notable changes is dropping the Java runtime files from the default installation, since we don't have the capacity to maintain security updates for it for 5 years. This leads to the removal of Freemind, a great mind mapping tool, as well as Geogebra, an algebra tool. The good news is that both packages will still be available a few clicks away in the Ubuntu Software Center.
iTalc is being removed and is replaced with Epoptes, which is actively developed and integrated in Edubuntu.
Better planning and support
Having long-term Edubuntu releases will allow administrators to better plan and co-ordinate software deployments and upgrade. It also allows contributors to better focus backports of packages and encourages developers to focus on the supportability of the product.
Edubuntu will also have point releases for the 12.04 (Precise Pangolin) release. This means that updated installation media will be made available that will include up to date packages for all software shipped. Point releases will be made along with the Ubuntu release schedule.
The Edubuntu 12.04 LTS proposal can be found on the Ubuntu wiki.