Forum Moderators: phranque
Web services are essentially methods of exchanging information without a web browser. For instance. RSS/RDF news headlines are a primative form of a web service. You put a code snippet in the code for your webpage and everytime someone views that page the code snippet initiates a request to the news headline server which serves up the latest batch of headlines which get parsed to screen on your webpage.
Next step up is RPC (remote procedure calls) which essentially allow you to call a procedure on a remote server which executes some code and returns some data to you.
Then you get into more advanced stuff like SOAP, WDDX. Similar to RPC only more robust.
Go get your feet wet at O'Reilly [oreillynet.com]. That should keep you busy for a while. ;)