Papaya is an application you run on your server that makes it easy to share large files. I see it as a mix between Mac Os X’s built-in File Sharing and Web Server.
When you drag a file to Papaya, the file is uploaded and the download URL is automatically copied so you can paste it into an email address or a chat window. When uploading a folder, Papaya can either upload it with the same directory or archive it with ZIP or TAR automatically.
Papaya is 20 euros, downloadable from the official site.