MS Dynamics CRM contacts are stored in the Dynamics CRM SQL database. You can use the Dynamics CRM Webservices/SDK ( http://www.microsoft.com/download/en/details.aspx?id=24004 ) to access contacts and create a synch app with Active Directory.
As far as I know you can use LDAP to run queries against AD, never used it myself. Check out http://technet.microsoft.com/en-us/library/aa996205%28EXCHG.65%29.aspx

Good luck and thanks for your comment.

My company is thinking about implementing CRM in-house and Im wondering where the CRM contacts are stored, will those contacts be available to other Exchange or Sharepoint users?
We currently store contacts in AD and is available to everyone with Exchange GAL.
If not, is there an API to create a synchronization program between Active Directory and MS CRM?

Best regards,
Steffen

Thank you for the kind words!
A few more MS CRM related posts are coming up, so keep watching this space.

Kind Regards,
Pieter

I just saw your blog entry on the integration with Microsoft CRM and just
wanted to let you know that we use Add-In-Express to integrate our Outlook
integration to many different CRM systems. We currently support Salesforce.cm, Microsoft CRM and SalesLogix and will be expanding to other CRM’s. Add-In-Express is a great product and your support is excellent. Keep up the good work.