Dr. Arditti's book on micropropagation is out of print, but his brother is selling photocopies for less (marditti@dslextreme.com). From what I understand it is a good book. Also, there's Aaron Hicks' Orchidseed Germination Manual available from his website Orchid Seedbank Project
Our Books. Hicks' book is good and covers the basics. An Austrian couple has a nice informative website you should also check out
Lotte & Thomas Orchideen. There's also a book by the Kew garden people available at ravenroostbooks.com.