xls input forms on the web
 

I've searched but not found a straight-forward answer to this question:

How can I put an Excel form on the the web that can be filled out by the user?

Via Google, I have seen many third-party add-ons/converters. Is this the
only way to go, or is there a better way? I use Excel '02 version. Do the
newer versions incorporate this "online" ability within the program?