Well, I wouldn’t really call this a fix and I don’t really know if I’ve got all facts for a decent how-too but this little manoeuvre helped me getting sound from the internal speakers on my Lenovo T61 in Fedora 11. Yah, that’s AMD64/x64 by the way.

I found out after a bit of googling that sound really is working, but only when using the head-phone jack. So i tried it out and much to my amusement it was true. This means that the sound-card has been discovered and enabled.

Anyway. Opening a terminal and running alsamixer -c0 will enable you to turn on the internal speakers.
In the mixer, step right until you get to “speaker” and you might find that it is muted by the MM above it. Press M and it will turn to 00. Now check your master volume and start enjoying the sound… i hope.
If this doesn’t work, you probably need to apply some patches and stuff found by… eh… google.

Good luck!