I've worked with Acrobat and Livecyle for a while doing stand alone forms, but my latest project would work best if I created a HTML/XML webform that the clients just typed in a variety of data into fields and then hit submit and from this information this created a PDF that was filled in properly and the correct text is in the correct sections and they could then print this pdf out but the pdf would be saved on a server after they hit submit.
What kind of software solution would I need for this and (stupid question I know) how easy would it be?
Collecting the info on an HTML page is fine ...you cpuld submit as name value pairs, then turn the input into an XML data file. That data file can then be used to merge onto the PDF file or import as the case may be. Once it is in a PDF then printing and submission of the PDF is a breeze. The negative is that you will have to maintain two templates (one for the PDF and one for the HTML).
If you have a server involved you could use LiveCycle Forms as it will allow you to have a single template definition that can be displayed in HTML or PDF. That is an expensive solution for a single template but if you have many templates then it might be worthwhile.