Check these sites for discount hotel rooms
http://www.i4vegas.com
http://www.travelworm.com
http://www.tripres.com
and US Airways Vacations has good air/hotel packages from many cities to Vegas. Check them out too.
http://www.usairwaysvacations.com
Also check out the message board at Las Vegas Talk. You will get lots of info and tips on planning low rolling trips.
http://www.lvtalk.com