According to an Apple press release, anybody who buys a new Mac between June 6th and whenever Lion hits the market will be eligible for an "Up-To-Date upgrade." In the past, Apple's UTD upgrade has offered the next OS for about $10 but Lion seems to be bucking the trend and will be available gratis. The offer does have to be redeemed within thirty days of purchase. [Apple via MacRumors via TUAW]