Ever since Apple introduced the Active Directory plugin to the Directory Utility in OS 10.4, single sign-ons using AD credentials among Mac and PCs has never been so easy.  The setup has been called the Magic Triangle, and is best described as follows.

User authentication is always handled by the AD domain. Computer authentication, user and computer preferences are handled by the same OS server that the client has...Windows to Windows, Mac to Mac.  The only exception is that the Directory Utility AD plugin will look at the user's home folder setting in AD to mount the network home folder.