Hey.. welcome to the world of FREEDOM.
you can just start by making your pc dualboot with gnu/linux and windows. install/replace all of your windows software by GNUwinII softwares. so that you can try gnu softwares on windows too. it will help u to be accustomed with gnu softwares.
and ofcourse besides this keep spending much time on gnu/linux. and after somedays just kick the windoz out ! simple
now the difference between two packages. i think u mean two different gnu/linux distro ! right? well, basically it's all about bundled software and environment..aka flavor.
lots of good tutorials are available on net and in gnu/linux itself. u can
always refer those. but i prefer a book " Running Linux" from O'Reilly.com - Shroff Publication has it's Indian reprint. this is one of the best book on gnu/linux. u must have it if u wish to master gnu/linux.
as per as my first gnu/linux is concern it's kool. when i was first introduced to gnu/linux, there was all command line, very little graphics. Installation was kool, no gui, no mouse support, no autopartition. But overall it was pretty kool.
