Can I block emails from certain senders?
http://gmail.google.com/support/bin/answer.py?answer=8151
Can I block emails from certain senders?
Gmail users can't currently block messages from specific email addresses or domains. In the meantime, you can set up a filter so that unwanted mail bypasses your inbox. To set up a filter, follow these easy steps:
1. Click 'Create a filter' under the search box at the top of any Gmail page.
2. Fill in the appropriate fields with the the filter's criteria, and click 'Next Step.'
3. Choose the action you'd like to take on the message by checking the appropriate box (in this case, we suggest checking 'Move it to the Trash').
4. Click 'Create Filter.'
After you create a filter, the filter's rules will automatically be applied to incoming mail. You can edit your filters at any time by clicking 'Settings.'