Ah ha! I found a good article on recovery using a snatch strap. For some strange reason, you can't use the url to get to it directly, but if you do a Google search for 'snatch strap', find the citation 'WHEELS24.co.za'. Amazingly, the picture that accompanys the article is that of an XJ in the mud. The article also talks about how to connect two straps using a dowel.
Tim C.