Hi David,
There are two methods of print via web.
1) HTML
2) PDF
Both methods require you to set the iDestination to which is chosen. If html is chosen, they can select the print from the file menu.
PDF requires a little more effort. You'll need to save the pdf to a temporary file on the server and then download the pdf to the end users machine using FileDisplay(). You'll also want to setup a windows task schedule to clean the pdf files from the temp folder.
Cheers!
Ken