Uh....not too sure about them all being rooted.....don't believe that is true.
If you want to have a good guide, I pasted this from another topic. It is very useful.
Two very helpful sites.
Rooting 2.1:
http://forum.sdx-developers.com/android-2-1/de03-instructions-for-flash-recovery-root-custom-patch/?PHPSESSID=vq3jep506mjr96av0csgmk1814
Rom Kitchen (quite useful):
http://www.sdx-downloads.com/custom/
Second site has some configurations that include root. I used it to install a ROM and live wallpapers with different boot images, and it worked really well. I used the first site to root it, and it includes all the drivers/software you need, which is very convenient. Just used the second site to customize.