check out cyanogen forums, or modaco forums about rooting. Very helpful information on those sites and guidelines on how to root. Rooting is basically unlocking your phone to be able to customize it how you want it. Custom roms, changing the speed of it,
Started rooting with cyanogen about to try the desire rom. Cyanogen to me is stock n1 rom basically but more customization plus free tethering, and wifi hotspot.