Some developers here have an ASP.NET application in which they need to query the Exchange Server Address Book to display a filtered list of people to choose from for generating an e-mail.

Some time back I was querying the Exchange Server using a free third party .NET dll but am wondering if a better methodology exists now for accomplishing this task. Since I have not tackled this task recently, is anyone querying the Exchange Address Book data store and how are you accomplishing it?

Thanks,
Bill