At Blackhat Europe 2008 Chema Alonso and Jose Parada Gimeno from Microsoft Corp published a great talk about LDAP Injection & Blind LDAP Injection. 

Here are the links to thier presentation, whitepaper and tools

http://www.blackhat.com/presentations/bh-europe-08/Alonso-Parada/Whitepaper/bh-eu-08-alonso-parada-WP.pdf

http://www.blackhat.com/presentations/bh-europe-08/Alonso-Parada/Presentation/bh-eu-08-alonso-parada.pdf

http://www.blackhat.com/presentations/bh-europe-08/Alonso-Parada/Extras/LdapInjector_final.rar

Mike