Hoarding has gotten an amazing amount of attention in recent years. It isn't an easy disorder to treat but can be treated quite successfully with some persistence. Here are some good resources on CBT with hoarding:

Steketee, G. and Frost, R.O. (2006). Compulsive Hoarding and Acquiring: Therapist Guide. Oxford University Press.

Steketee, G., and Frost, R.O. (2006). Compulsive Hoarding and Acquiring: Workbook. Oxford University Press.

Frost, R. O., and Steketee, G. (2009). Stuff: Compulsive Hoarding and the Meaning of Things. Houghton Mifflin Harcourt

Tolin, D.F., Frost, R.O., and Steketee, G. (2007). Buried in Treasures: Help for Compulsive Acquiring, Saving, and Hoarding. Oxford University Press.

and on the Web: International OCDF Foundation Hoarding Center (http://www.ocfoundation.org/hoarding/)