They'll be out in (US) Spring 2006 - at least that is what they said at the CES this year.
Yes, you need new hardware.
Discs will be around $23 - well those are the prices Sony has set for their
titles they have already planned for release
They will, at the time of launch, retail for around $1,000 for a standard player and up to $1,800 for a "deluxe" player. Of course, you'll be able to pick up some cheaper, but then you're sacrificing possibly quality.
They'll get cheaper, just like DVD Players did, when they become popular.
