google it noobs
the 2600xt's (certain or all of them, not sure) are able to output audio from the dvi connectors, using a special adaptor to convert that into hdmi.
http://img5.pcpop.com/ArticleImages/500x375/0/483/000483992.jpg
a normal dvi-hdmi cable will not, afaik, carry sound. you will also only get 2channel PCM or dd/dts, and none of the HD audio formats.
for now, if you want it all, analogue is the only way.