there is a good book that covers most of the issues about digital library.(from Web4lib)
see:http://portal.unesco.org/es/ev.php-URL_ID=11613&URL_DO=DO_PRINTPAGE&URL_SECTION=201.html
Title: How to Build a Digital Library
Autor(es) Ian H. Witten and David Bainbridge
Foreword :by Edward A. Fox