This is how I do it:
1. Down load attachment file from email
2. Open attachment in TextEdit
3. Look to the bottom of the text file and find URL (e.g. "http://www.wimp.com/tinyspaces/" on a recent email.
4. Copy URL to browser address line and press RETURN
5. View on browser page and download from there, if you're interested (I use "RealPlayer Downloader")