Copyright law runs the gamut from tedious to vague, and is even more so when it comes to the new world of online media. If your work is being infringed there are some immediate things can be done to stop it.
Another more formal way of protecting images is to use a service like PicMarkr. The free, online, tool adds a custom watermark to any image. The site is easy to use and can pull photos directly from your hard drive. The watermark can be either text or an image such as a logo.
Photos of a local event that may not have been caught by a news crew often pop up on Flickr, but take in a few moments before clicking that download button. The site can be used as a resource for non-commercial websites under Creative Commons license, which excludes a lot of media outlets, so be sure to contact the photo creator for permission. An alternative is to set up a group pool, like the one created by KPBS as a repository of photos of the recent San Diego wildfires.
If text is the problem, Attributor is available to help. The site, which recently partnered with the Associated Press, scans the internet for illicit copies of your content and requests immediate removal. I cannot vouch for its accuracy, but it sounds like a great solution.
Most major news organizations have a cadre of lawyers on hand to deal with these issues and should be consulted should they arise. For more information on media law, check out the First Amendment Project, which has a great number of resources available to journalists.
Finally for a humorous explanation of copyright law, take a look at the video below by Professor Eric Faden of Bucknell University: