Xandros introduced a new Linux-based instant-on operating system named Presto:
Presto is an easy to install program that works with most Windows XP and Vista PCs. Next time you turn on your computer, you’ll have the choice of running Windows or Presto. With Presto, you’re automatically connected to your network and productive in seconds. You can easily access your Windows files. When you’re done using Presto, you can turn off your laptop instantly. You can even uninstall Presto using the Windows Add/Remove Programs control panel.
The beta version of Presto, which is Italian for quickly, will be available over here on March 16, 2009. Here's a screenshot of Presto: