Canonical has released the first beta of Ubuntu 10.04 "Lucid Lynx" yesterday for Desktop, Server, and Netbook editions and Server for Ubuntu Enterprise Cloud (UEC) and Amazon’s EC2. This version of Ubuntu is to become a LTS release.

The Ubuntu 10.04 family of variants - Kubuntu, Xubuntu, Edubuntu, Ubuntu Studio, and Mythbuntu have also reach their first beta yesterday.

The new features in Ubuntu 10.04 since 9.10 includes:

• Default search engine has been changed to Yahoo! The default Home Page will use either Google or Yahoo! depending on user setting.
• Ubuntu 10.04 Beta 1 includes the 2.6.32-16.25 kernel based on 2.6.32.9.
• Kubuntu 10.04 Beta 1 features the new KDE SC 4.4.
• HAL has been removed fully from the boot process, making Ubuntu faster to boot and faster to resume from suspend.
• The Nouveau video driver is now the default for nVidia hardware.
• Built-in integration with Twitter, identi.ca, Facebook, and other social networks with the MeMenu in the panel.
• Two brand new themes, Ambiance and Radiance. New wallpaper and icons are also included.
• Ubuntu One Music Store.

You can view the full changes details and download details here.