Try this website. It has ALOT of usefull information on carpet pythons. And can answer your question about what size of enclosure they need. Generally for an animal that will be around 4-6' in length you will need around 5-6 sqaure feet of floor space. It is also preferred that you give them an enclosure that is about 2' high and provide some climbing materials.

http://www.acreptiles.com/carpet_python_care.htm

Hope that this helps.