Here is a guy who made his own
Pyramid Foam Sound Absorbers using acoustic foam from
www.partsexpress.com and some panels from a hardware store. Quite a good link with pictures.
I also recommend a book by F. Alton Everest called "Sound Studio Construction on a Budget". While orriented towards production studios, he does explain the major concepts and includes 2 chapters on home theater rooms.
I think this book is sub $20 at Amazon.
Anthony: while we dont like people to promote their goods or services, any expertiese you have in these matters is welcome. Please feel free to comment on what you know, have done, found that works/does not work, etc.