Subnetting Class C using /25 HELP!

Anyone who knows how I can split up a Class C address using a /25 mask, I would appreciate some technical knowledge. In my book the subnet id’s from this would result in the zero and broadcast ID’s meaning you could not really use them. I am told that there are situations that you can. This is the only solution to my trouble, and I would like to find more information on how to do it, and specifically how to setup my Windows NT 4.0 DHCP server to hand the correct Addresses to each subnet.

Any help would be appreciated.