Simple, really simple, example of web services

Web services have been around for a while now.  It looks to me like a lot of the information, tutorials, wizards, and examples that are available  have become stale, superseded, or otherwise abandoned.  There also seems to be several different approaches with various pluses & minuses.

I want to write a web service that is about as basic as it can be and still legitimately deserve to be called a web service.  Seeing it in action will, I believe, help me understand what all is happening.

To that end I have a web page where someone can enter a date and I have an Apache server set up for serving the response.  The web page HTML & javascript will send that date as a request to the iSeries Apache web server where an RPG program will calculate the Day-of-the-Week (Sunday through Saturday) and return that answer to the requesting web page and be displayed to the user.

Any and all comments, suggestions, pointers and references will be appreciated; especially when geared toward the novice.