Finally the 64 bit edition of Flash is somewhat available again! It's called Flash "Square". I tried it last night on my dual core Atom HTPC running Debian Squeeze. It was amazing. Full screen HD YouTube videos play smooth as butter. I've never seen this with Flash in Linux! Amazing!
By the way I still hate Flash but you gotta live with it so...
See my edits in the Debian wiki on how to install on a 64 bit platform: