Simply contact the offending website owner's host if and when a violation happens and they will likely take the site down for you.
Well, there's nothing that you really can do as a pre-emptive strike. Just try and include references to key terms that make it easy for you to find content stealers.
Here's another tip. Every week or two simply search Google for a unique phrase in your story with quotes around it. That will find any content thieves for you without costing you a penny. There's other services like Copyscape that will also help you for a fee.
Sometimes deliberately planting typos in the text will make it much easier to search for copyright infringers, but that's something you only want to do in moderation, if at all. One thing you could do is put "Copyright NoahM - all rights reserved" at the foot of each page. Link this text to a page explaining what copyright is, and why it is not all right to cut and paste your content wholesale. Although this gives you no extra legal protection, it helps to educate. A lot of infringement happens because some people just don't know any better. Whilst you can't guard against stupidity, you can at least make sure they don't have the excuse that they didn't know. Make it as explicit as possible.
Thanks for all the advice but I'm still questioning -- How do you prove content was your first. What if the person who copied you just says the content is his? A home-made method of copyrighting before the internet age was to mail yourself your manuscript and leave the envelope unopened, then you sort of have an official government seal (a postmark) establishing when you created that content. What is the internet age's version of this trick?
You could announce your articles on e-mailgroups (like yahoo-groups). that would get the link on a dated, independent page.