This is not just related to COD4. A friends PS3 died a week or so out of warranty, and he hadn't even played COD4. With the amount of people playing COD4, it's probably more coincidence. Soon it'll be people playing GTA4 that are having their lasers pack up.
This seems be am increasingly occurring problem (I've been saying for ages this is Sony's RRoD equivalent).
If it's out of warranty, Sony charge $150 to fix the laser.
Personally, I think if this is as common as it sounds, people should be kicking up a stink. Hell, it happened with the 360 owners, and MS extended the warranty to 3 years for the RRoD. As much as PS3 fanboys bash the 360 users for the RRoD, at least they can get there console fixed if it happens after one year and one week. Sony will tell you to take a hike though.