It depends on your email client. Here is a  comprehensive list of email client programs and methods to see the email headers.  We have posted the steps for Outlook 2007 and Outlook Express below for your convenience.

[A]Microsoft Outlook 2007 users:

1. Open the email message.
2. Under the Message tab, in the Options group, click on the Dialog Box Launcher icon.
3. In the Message Options dialog box, the headers appear in the Internet headers box.

[B]Outlook Express users:

1. Double click on the spam message
2. Click the "File" menu in the message window
3. Click "Properties"
4. Click the "Details" tab
5. Click "Message Source"

To report a message as spam for the SpamWeeder system, please send the header information to analyze@webservio.com. To send the header information, please copy (Ctrl A then Ctrl C) and paste (Ctrl V) the information into a new email message.