Learning Web Based Application Development

and how much functionality you need / want client side and server side.

If you were to squint and define as an app which you asked for the current time in amjor capital.

You could do that all clientside. you could do request and response from a server.

It could be javascript on the client, silverlight, a java applet, etc. ASP, JSP, PHP, ISAPI, NSAPI, CGI server side

They key thing about web apps is deciding what to do where. The cost of those choices, either in speed , efficiency, maintenance of state, code complexity, and of course security.

If you've done client server, you've done web development. The difference is merely a constraint on the protocol you used to communicate and the base tech you are alowed to develop with.

Don't know what tech you are going to use, but a secure logon screen that shows a page with Hello [Username] from some form of look up on the server is a very good starter.

I'd start with a LAMP setup and take baby steps with building some basic apps...