how do you buy rims?

I know all these rims and wheels have their own specifications... so can anyone explain it, or have an url with some info?

and, I really like the ENKEI wheels, so if anyone has them, anything you want to say about them would be cool.

 

go here tirerack has good info on rims and tires but not the best prices......
http://www.tirerack.com/index.jsp

and other online tire places
http://www.rimone.com/
http://www.wheelmax.com/
I got my rims from here
http://www.whalentire.com/
http://www.victoriatire.com/
http://wheelsnstuff.com/index.html
http://www.washingtontire.com/
http://www.performanceplustire.com/
http://www.discounttiredirect.com/