SQL Server 2005 - Support for RPC over Http

1. Can Clients onnect to a SQL 2005 DB via RPC over http?
2. Can SQL 2005 Clients Synch across the Internet to a SQL 2005 Server
using RPC over HTTP?
3. What ports need to be open for SQL 2005 Clients to synch to a SQL 2005
Server across the internet via a VPN? or RPC over HTTP?

Regards
Stuart