I've installed my first exchange 2007 server, the install for the Hub transport failed because of a known installation bug but I re-ran it from the command line with the /LegacyRoutingServer switch and it created the connectors between the two.The mail I try to send is stuck in the routing group connector's Queue.The ExchangeLegacyInterop security group is there and the 2003 bridgehead is a member.SuppressStateChanges is on. I've tried deleteing the routing group connector and added one manually but the problem persists.

Problem resolved. I tried to telnet to the exchange 2007 SMTP VS and received the error "452 4.3.1 Insufficient system resources" I turned off resource monitoring in EdgeTransport.exe.config, restarted the transport service and mail began to flow. The disk that holds the queue apparently need more than 2 gigs of free disk space. Disk space is at a premium for me however since my production servers are SAN hosted Virtual Machines.