If port 1501 is taken by another process at the time of AD FS 2.0 service start, you will find event ID 364 in the AD FS 2.0/Admin log in Event Log with the following description:
MSIS7004: An exception occurred while connecting to the federation service. The service endpoint URL 'net.tcp://localhost:1501/adfs/services/trusttcp/windows' may be incorrect or the service is not running. ---> System.TimeoutException: The open operation did not complete within the allotted timeout of 00:01:00. The time allotted to this operation may have been a portion of a longer timeout. ---> System.TimeoutException: The socket transfer timed out after 00:01:00. You have exceeded the timeout set on your binding. The time allotted to this operation may have been a portion of a longer timeout. ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
Net.TCP Port Sharing
http://msdn.microsoft.com/en-us/library/ms734772.aspx