I am often asked by students for resources regarding archaeology. Sometimes, by working adults as well - those that wish they'd spent some time doing some archaeological work. I've collected a few regular recommendations for everyone here; but this is by no means a comprehensive list. Please don't hesitate to ask questions if you want to learn more...
The Archaeological Institute of America (AIA): The oldest professional organization in the States, the AIA is where more classical archaeologists are active and it possesses a worldwide focus. This organization publishes the very accessible Archaeology Magazine.
The Society for American Archaeology (SAA): This organization focuses on the fieldwork and research of the Americas. If you are interested in Southwest archaeology, this is a good place to get started.
Access to this information has become remarkably easy with the advent of the web. Simply do a search online and you'll find no shortage of listings. If you are looking for some authority, the AIA maintains the Archaeological Fieldwork Opportunities Bulletin.
If you are looking to stay in the United States, or are a working adult looking for a short-term opportunity, I recommend the Crow Canyon Archaeological Center.
You can learn a lot about the field by reading the ramblings of folks that are active participants. Some of these folks are actually smart:
The Archaeology of the Mediterranean World: Bill has a lot of good ideas about new media, digital technologies, and teaching as well as history and archaeology
Ancient History Ramblings: You must read "The Voyage of PKAP Airship" as it explains a lot about archaeologists...
Corinthian Matters: David is an expert on the Corinthia; and I'm jealous of his header image because all of my efforts to capture the isthmus from Acro are hazy!