C'mon, Jonathan! Network analysts spend years learning how to sift through protocol data. How do you expect me to learn this in an hour?
The key here is to limit the scope of what you're learning. Although you're perfectly capable of learning the various protocols and service nuances that underlie the everyday programs and services that you know and love, why would you want to? (That is, unless you need to.) Remember that protocol analyzers are simply an effective way for you to verify that which your black box troubleshooting skills have already shown you. Don't get discouraged if you don't understand everything you see on the decode screenjust remember: "Which of these things is not like the other?" and use a little common sense, and you'll do very well. If you feel you need or want to dig deeper, grab a protocol book and have fun. But in many cases, that won't be necessary.
Where can I download a free analyzer?
Check out http://www.ethereal.com/download.html. It's awesome. If you're looking for Win32 analyzers, free demos are about all you can expect. Check out Finisar, at http://www.finisar.com/virtual/virtual.php?virtual_id=download, for a trial version of Surveyor.