thank you very much for a useful link, job_seeker.
have you used their service for your I-94? is that mailing address they provided valid and works?
I have not sent my I94 and supporting documents yet as I am still looking for official receipts of seminars I have attended in Canada, to prove I have been here before and after the expiry of my I94. But I intend to send my documents soon as I have to be back to the US again sometime in July and I don't want to have any trouble at entry considering they are again beefing up their security and may be even more strict with their entry rules:(