Here is the method to report spam to spamcop from a gMail account:
From the webmail, view the source:
1. Open the email you wish to report (most of the times, it's in the spam folder).
2. Click on "More Options" (between the "from" email and the time).
3. Click "Show Original" (last link to the right on the last line of the headers).
4. A new window will apear (if you don't have a popup blocker).
5. Select all the text in the new window (CTRL+A) and copy in the reporting box on spamcop.net.
gMail does not currently permit forwarding as attachments so you cannot use email reporting.
P.S. If you wish to have a gmail account, I have 50 invites. Just pm me