Im betting HDMI cables will be a part of bundles people are required to purchase at places like Best Buy if they want a PS3 at launch simlar to what happened with the 360.
And I lucked out, I had to buy a DVI/HDMI adapter which I managed to find online for $10 because my tv only has DVI, but I got an HDMI Cable with my first HD Directv System and then I got another with My HD Tivo, and I got an HDMI cable with my upconverting DVD player, so I have 3 now, plus a ton of component cables.