Apple has confirmed in it's Q3 financial earnings press release today that it will release Mountain Lion tomorrow for US$19.

“We’re thrilled with record sales of 17 million iPads in the June quarter,” said Tim Cook, Apple’s CEO. “We’ve also just updated the entire MacBook line, will release Mountain Lion tomorrow and will be launching iOS 6 this Fall. We are also really looking forward to the amazing new products we’ve got in the pipeline.”

Mountain Lion will be available from Apple's App Store on your Mac.