The next ubuntu stable version is going to be released on 23rd April 2009.If you want to order your free CDS use the following link
https://shipit.ubuntu.com/
If you want to know new features in ubuntu 9.04 as follows
* Linux kernel version 2.6.28
* A new notification system
* Faster boot times
* GNOME 2.26 desktop environment
* Community desktop themes and brand new artwork
* Evolutionary EXT4 filesystem
* Support for many new devices (wireless, webcams, mobile phones, etc.)
