Server 2008 NPS

Hello,
I am attempting to configure a stand alone radius server to authenticate to
active directory. My active directory box is a 2008 box as well. The end
goal is to have wireless users authenticate to the radius server and be
placed on a vlan based on the active directory credentials they use. If
someone could give me tips or point me to a good how to guide, that would
help me so much. I have been looking on google and while I did find some
good examples none told me how to configure it with vlans assigned to
groups. Thanks so much!