A few good ways to learn linux:
some people offer free shell services allowing you to connect to their computer to learn linux
http://www.freebelt.com/freeshells.html I haven't checked any of the links this is an example http://www.google.com/search?hl=en&l...ls&btnG=Search
you can download an SSH (Secure Shell) client for windows to connect
http://www.chiark.greenend.org.uk/~sgtatham/putty/
another good way is to use VMware
http://www.vmware.com/
VMware Workstation is a bit pricy but they now offer a free VMware Player,
http://www.vmware.com/products/player/
its limited in the aspect you can only use VMware Images that have already been made, to make your own you would have to purchase the full workstation version.
the major downfall for VMware is the overhead of running an OS on top of an OS