I had heard this might be coming, but today Intel made it official. The Performance Tuning Protection Plan is a $20 - $35 plan that you'll be able to purchase either from Intel or one of its approved resellers, starting today. Typically if your CPU dies because you push it too far while overclocking, it's not covered by Intel's 3-year warranty. If you purchase the PTPP for your CPU however, you are given a single replacement free of charge. Any future damage isn't covered and the replacement is only available as long as your CPU is still covered under its original warranty. And no, you can't buy multiple plans for the same CPU.

A table of supported CPUs and PTPP cost are below:

These plans are only available on retail, boxed CPUs. The plans can be transferred between owners if you sell your CPU and you're allowed to own multiple plans, just not on the same CPU. Finally, you can't request a replacement CPU in the first 30 days of purchasing the plan. 

This is very much a trial for Intel. Intel will only offer the PTPP for the next 6 months, at which point it will likely regroup and measure the effectiveness of the program. Intel also reserves the right to change the terms of the plan or discontinue it at its own leisure. Presumably if you purchase one of the plans however you'll be covered until your warranty runs out. 

Most end users (including enthusiast overclockers) will likely not benefit from this additional coverage. It's really for the competitive overclockers and the folks who are truly pushing the limits of what Intel's silicon can do. I can definitely see the value for the hardcore overclocking community.