SMTP is Internet email.
BCP is a utility that ships with SQL Server. It can be distributed to your partner and can run on any windows workstation. The workstation will need the MDAC data components and port 1433 open to your server.
If this is not a fairly trusted company, then I would recommend they file transfer to you. there are any number of ways to do this.
Then you can schedule something to import the file. Once you have more definite information on how this can flow, start a new thread and we will help.
One note, if you want to automate this, then the file you recieve should be in the same format all the time.