C class ip NNN.NNN.NNN.HHH
B class ip NNN.NNN.HHH.HHH
A Class ip NNN.HHH.HHH.HHH

N=network portion H=host portion(your computer)
The class of ip u have depends the size of your isp
AOL has many A classes that they breack down into b and c classes

Bell south (phone company if u dont know) sells Cclasses ips to lower isps

I'am Bored so that y i posted this stuff that most programers/network ppl allready know