For 2008, the new funding rules allow a company to contribute and deduct an amount that would leave the plan with assets that cover up to 150% of unfunded Current Liability. (Right?) There was some speculation that that provision would reach back to both 2006 and 2007 also.

Does it?

"some speculation"? There is no speculation... the maximum was increased effective in 2006.

Read any summary of the Act and it will explain how it is determined.

It seems like it could be a tremendous boon to a company with a pension plan that is currently nearly fully funded and has plenty of cash looking for a place to put it. Do you know of a link where I could read a summary? Thanks.

I'm not sure about the "tremendous boon" but it may be useful for a company who has a lot of cash and wants to drop it into the plan. Keep in mind, they didn't change the onerous excise tax on reversions. Once the plan is deposited into the plan, it is in the plan and can not be removed without paying a heavy tax. So if the company is going to purposely overfund its plan, it needs to do it with eyes open that the money can not be recovered.

There are also special rules related to HCEs if you are dealing with a small plan.

As far as a summary, just Google PPA 06 or go to benefitslink.com and search recent articles for PPA 06 Summary.

And don't overlook that the 150% CL rules for 2006-7 are not identical to the 150% rules for PPA in 2008.
2006 and 7 will allow 150% of the current year accrual, while 2008+ will not.