The University of Maryland has a comprehensive section on psoriasis.
There is a comprehensive review of home phototherapy published in the Dermatology Online Journal 16(2):1
Although psoriasis is the most common condition to be treated with NB-UVB other conditions which can be treated are vitiligo, mycosis fungoides, polymorphic light eruption, actinic prurigo, erythropoietic protoporphyria (desensitisation protocol) and vitamin D deficiency. There is a wealth of information at phototherapysupport.net
Philips Phototherapy website gives more treatment information for various skin conditions.