Google has settled a class-action lawsuit led by plaintiffs Lane’s Gifts and Collectible’s and Caulfield Investigations. Here’s Google’s new deal for you: If you can prove that you received invalid clicks, you’ll get a credit on your AdWords account.

How does that differ from the old deal? Now you can reach clear back to the program’s inception in 2002, instead of dealing with the previous 60 day window.

Of course, the same proof of fraud criteria Google has always applied still rules. Which means your probability of meaningful reimbursement is slightly less than your chance of being run over by drunk chicken driving a Masserati.

Ironically, just last week a Google flack limited the pay-per-click fraud for Email Battles to “more a question of targeting, and whether or not we charge the advertiser is the real click fraud issue.”

Apparently, a certain set of lawyers agree wholeheartedly… The lead in this case being Dallas attorney Joel Fineberg, a guy who others of his ilk selected twice as Texas Super Lawyer. In addition to click fraud, Fineberg’s currently tracking the maker of a LASIK eye surgery device and manufacturers who used cobalt in products.

Fineberg’s pay-per-click hunt is far from over, as Yahoo and other cost-per-click sellers are still on the hook. And we’re betting Google hasn’t heard the last its PPC problems either.

But this time Goog’s agreed to dribble out up to $90 million in advertising credits, minus legal fees.

Our guess for Google’s total outlay: $15 million cash max, with a miniscule amount for AdWords credits. What’s yours?