Let Outlook publish your files directly to a SharePoint library instead of sending them as attachements. This add-in does that, automatically or after your choice, and leaves a link in the e-mail instead, thereby allowing you to make better use of your intranet and Exchange server. Outlook is good for a lot of things, but not for file transfers.
Works with any Frontpage or WebDAV site but of course best with SharePoint document libraries.
Free 15 day trial. Single User license 49 USD. Organizational license 395 USD including one year of support. Video demonstration + downloadable Word-manual and slideshow online. Supports Windows Vista and Office 2007.