Howtogeek posted a guide on installing Ubuntu Netbook Edition with Wubi Installer

Ubuntu is one of the most popular versions of Linux, and their Netbook Remix edition is especially attractive for netbook owners. Here we’ll look at how you can easily try out Ubuntu on your netbook without a CD/DVD drive.

Netbooks, along with the growing number of thin, full powered laptops, lack a CD/DVD drive. Installing software isn’t much of a problem since most programs, whether free or for-pay, are available for download. Operating systems, however, are usually installed from a disk. You can easily install Windows 7 from a flash drive with our tutorial, but installing Ubuntu from a USB flash drive is more complicated. However, using Wubi, a Windows installer for Ubuntu, you can easily install it directly on your netbook and even uninstall it with only a few clicks.

Install Ubuntu Netbook Edition with Wubi Installer