hi m8,
yes linux is a good operating system but in my opinion if you are running a desktop PC just stick with Windows - linux really comes into it's own on Servers etc etc.
if this is going to be your first time playing with Linux stick with one of the more common distributions such as Mandriva or knoppix, debian as these are really easy to install even for the first time user!!!!
i am also fairly certain most if not all distributions of Linux will dual boot with XP!!! as is the case with everything though always best to make a backup.
a good resource is
www.distrowatch.com
some other links to distributions and downloads:
www.mandriva.com
www.mandrivalinux.com
www.debian.org
www.knoppix.com
just as another reference - if you do a good search on "linux live cd", you shuold be able to find some ditribution of linux that will boot from a CD without endangering your XP install - might be useful if you just wanted to have a quick look at linux.
hope this information is of some help to you