I've successfully configured the outgoing emails for Sharepoint & it is working fine.
We are planning to deploy this solution in an internet facing site where any user can register & get a username & password. By default when you configure the receive connector in Sharepoint it accepts emails only for internal domain ie., the domain exchange is routing emails for.
In our case since it can be any user, I'm not able to get the Membership webpart to work for external users ( it works perfectly for internal users). I was thinking about creating a send connector in exchange 2007 and linking both the connectors. Any other ideas would be appreciated.