Don't have a v5 myself, so I haven't verified everything but you should find everything you need here: http://www.bitsum.com/openwiking/owbase/ow.asp?WRT54G5_CFE#preview I also recommend reading thru the DD-WRT WIKI: http://www.dd-wrt.com/wiki/index.php/Main_Page as well as the forums so you have an idea what you are getting into. Great firmware but there IS a learning curve. d- ps not a good idea to post your email address in forums... at least not in that form.
I have flashed my V5 and it worked like a charm. Better than a j-tag. Just rember to give it some time to re-boot it's self.