Frankly, I consider all Christian groups to be cults, it's just that some are populous enough and have enough political clout to be accepted as "mainstream."
Why fundamentalist churches are often cults (http://www.sullivan-county.com/news/fundie_cults/index.htm)
Sects and Cults of Christianity (http://www.religion-cults.com/Cults/Christian/C-CULTS.htm)
List of groups referred to as cults (http://en.wikipedia.org/wiki/List_of_groups_referred_to_as_cults) - not all of these are Christian groups
The Children of God (http://en.wikipedia.org/wiki/Children_of_God)