I know that this request was made a long time ago, but just in case anyone else is looking for the Porto Moniz camp site...
The Porto Moniz campsite was relocated to nearby Ribeira da Janela in September 2004.
[
www.madeira-camping.com] gives details of 3 campsites in Madeira, but their Porto Moniz details are definitely out of date - I'm not too sure about the other two campsite details.
[
love-madeira.com] gives details of the Ribeira da Janela campsite, but doesn't have online booking.
If you want to camp rough in Madeira, I believe officially you need a permit. Contact the Office of Tourism:
[
www.madeiraislands.travel]
Their email is given at the bottom of the page.