I'm not sure I understand the mystery. Are these pdf files generated by PHP or stored in a database?
If they're plain-old pdf files all you need to do is output the file path to a hyperlink.
<a href='some/path/file.pdf'>The pdf file</a>
If the browser understands pdf files it'll try and display it, if not it'll prompt the user for download. If Acrobat Reader is installed, Internet Explorer can display pdf files natively. Mozilla is capable of this as well.
Regards,
Rich
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The Spicy Peanut Project
http://www.spicypeanut.net
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