Is anyone aware of an "web-based" application that allows developers to browse an LDAP server and view objectClasses and attributeClasses? Ideally I would love something open source that is written in either Java or .NET.
You have generic tools like http://ldapweb.sourceforge.net/ (HP) and http://ldapusrmgr.sourceforge.net/
Many directory products come out of the box with very powerful web interfaces like Sun Java System Directory Server Enterprise Edition which is also "free". I believe with the DSEE webmin tool you can access other directory servers' data if you set up "virtual directories" as well.
You can also go way outside the box and use tools like OpenSSO to do basic directory editing (though it won't expose TOO many details of the LDAP install, just a method to edit the actual data.
I personally like Apache Directory Studio which is a desktop app based on Eclipse.