Sure - in inc_header.asp, look for the following lines (appx 505-508):
Response.Write """" & dWStatus("Perform a search by keyword, date, and/or name...") & " tabindex=""-1""><acronym title=""Perform a search by keyword, date, and/or name..."">Search</acronym></a>" & vbNewline & _
" |" & vbNewline & _
" <a href=""faq.asp""" & dWStatus("Answers to Frequently Asked Questions...") & " tabindex=""-1""><acronym title=""Answers to Frequently Asked Questions..."">FAQ</acronym></a>"
end sub
After that add the following (put a <% %> around the following):
<form action="https://www.paypal.com/cgi-bin/webscr" method="POST">
<input type="hidden" name="cmd" value="_xclick">
<input type="hidden" name="business" value="your email addy">
<input type="hidden" name="return" value=""default.asp"">
<input type="hidden" name="item_name" value="Forum Donation">
<input type="hidden" name="item_number" value="HPRSD">
<input type="image" src="http://images.paypal.com/images/x-click-but04.gif" name="submit2" alt="Donate through PayPal">
</form>
Change the part in red to your registered Email address at PayPal.
If your PayPal account is a personal one (instead of business), change the part in green to say "personal"