I'm looking for some software that will provide a service that resembles SendThisFile.com. My users generally turn to services like these when they are trying to send files that exceed the mail servers limits (either our own, or the recepients). I've offered to set up FTP accounts for users, but we find that some clients have a difficult time logging into an FTP site.
I could write something in PHP, but it feels a bit like I'd be reinventing the wheel.
What are other companies doing to transfer large volumes of data to clients or partners where the limitations of email are a restriction, and vpn isn't a possible solution?