Access Points and Active Directory

Hi,

We have got 10 Cisco Aironet Access Points . However we donot have a
AAA solution like Cisco ACS.

But we would like to authenticate wireless LAN users via Active
directory database before they can connect. Is it possible without a
AAA solution?  Are there any drastic implications if we do this .

Cisco ACS is expensive ...hence we donot want to buy unless it is mandatory!