Wow I had a tough time getting Flash to work on my new Etch AMD64 box.
I tried Gnash only to give up and wait for better versions on the way.
So I ended up doing a chroot by following:
http://alioth.debian.org/docman/view.php/30192/21/debian-amd64-howto.html#id292281
Next I downloaded Firefox from:
http://www.mozilla.com/en-US/firefox/
chroot into whatever you called and installed the 32bit sid,
So I follow the instructions on installing, which places it in /usr/local/ (in the 32bit chroot, of course)
chown root:root /usr/local/firefox
etc.(read the directions)
Now download the non-free flash plugin for linux at Adobe.
manually place
flashplayer.xpt in /usr/local/firefox/components/
and
libflashplayer.so in /usr/local/firefox/plugins/
finally set up sound by installing ALSA (in AMD64) and running
alsaconf
What I left out was some swearing, disbelief, glory, and trying so many things it was crazy. I hope I did not leave anything out but if you run into firefox not finding shared libraries, install them in the chroot using 32 bit aptitude.
I would like to try it again to see if it is as easy as it sounds here; and because I might have forgotten something.