AD with Asterisk

Is there way to integrate AD with Asterisk, i want a way by which when i create a user in AD it creates, assigns an extension to the user automatically. So as soon as the extension is assigned its added to asterisk and the extension can be used via soft-phone or anything that the person is assigned to.

Is there a way for this to be implemented or am i just not thinking right?. Any help/input will be appreciated.

Thanks!

Why not use Asterisk to do the auto-dialling itself?

(If this is Microsoft related, Asterisk can do LDAP lookups.)