The Ubuntu team has now delivered the beta version of Karmic Koala aka, the Ubuntu 9.10 operating system. Coming after six alphas, the beta build is based on the 2.6.31-11.36 kernel, it includes the GNOME 2.28 desktop environment and features improved startup times, the Ubuntu Software Center, the Ubuntu Enterprise Cloud (in the server edition), the Ubuntu One file sharing service, GRUB 2 as the default boot loader, an improved iSCSI installation process and lots more.
You can download the Ubuntu 9.10 beta (in all its flavors) from this page or have patience and wait until October 29 for the full release.