This sounds like a job for Mac OS X! Specifically, Automator + Folder Actions. It’s pretty easy to set up. You could conceivably make an Automator script that sends any selected Finder files (Folder Actions handle the selection process automatically), to a pre-selected email address. You might even find a sample Automator script online, as I imagine this sort of thing is a common task. Once everything is set up, you would have a special folder that you could save or drop files into, and the moment they enter the folder, the Automator script would run, sending the new files along.