Depends upon what Email client you are using, and whether or not they are accessing you from your own Website, and a dozen other things.
Generally, if you use Outlook, Outlook Express, or Thunderbird, placing the email address into your local SPAM folder will "block that specific addy from your Inbox and will go direct to your SPAM folder. (Just right click and Select - Add to Blocked List)
Or, you can create any local Rule you wish.
If you are using an online email client such as Yahoo Mail, just moving the entire message into your SPAM folder, or clicking to Mark as SPAM will do the trick.
Now comes the exceptions:
If you are dealing with a professional spamming enterprise, once they have your email address you can pretty much expect to be annoyed by them for quite a while.
They generally own dozens or hundreds of gibberish random email addresses.
Once you block one, they just switch to another.
If they are coming at you from a Website that you own, for instance, a Contact Us@ or Info@, or Sales@ type Website inclusion, you will need to talk to your Host or your WebMaster who has access to Account Based Tools/filters
Note: MobileMania, Have you resolved the issue in
http://forums.whatthetech.com/index.php?sh…mp;#entry677592
Per suggestions of Murray and Tijn ?