For what it's worth, here's a link to a whole slew of documents dealing with rights and responsibilities, page maintained by the UN. The Geneva Conventions are at the bottom of the page.
While googling for a list of signatories, I found this page on International Humanitarian Law. Among other things, this site has a database of treaties, with signatories. (Click the fourth link on the sidebar.)
And there's also www.genevaconventions.org, a reference guide maintained by the Society of Professional Journalists.