A good way to learn about Linux on a desktop without all of the hassle of configuring and installing Linux on your computer, is to install pendrivelinux.

This enables a user to boot and run a Portable USB Pendrive Linux compilation (based on Debian Linux), directly from a folder on a portable USB device, USB flash drive, external hard drive, internal hard drive, Ipod, etc… all without ever restarting your Windows computer. In addition, the user can install new programs, make changes and save personal files, allowing the operating system and any changes to be optionally restored on the next boot.
Pendrivelinux can be run from within Windows 98, 2000, NT, XP or Vista without rebooting. It runs from it's own directory requiring absolutely no installation on the host PC. This is the perfect solution for those who's computer can not boot from a USB flash drive.