Email is super-convenient though, and honestly I can't say that I've ever had an email just vanish into the ether, though certainly that's possible. How often does Accounting lose an expense report or receipt? I bet it's more often than emails get lost... especially intra-company emails.

A simple web page on the company intranet that let you upload the scan, and key in a description and amount, would be more reliable but somewhat less convenient. It's a trade-off.