Apple has just released a new OS X 10.8 Mountain Lion Developer Preview about a month after the last release. Dubbed Mountain Lion Developer Preview 3, build 12A178q is the third beta release of the company's next major desktop operating system. Developers can grab a download redemption code in the Apple Developer portal, which will be used to get the update from the Mac App Store. OS X 10.8 Mountain Lion will be publicly released late this summer, but anyone with a Mac developer account can get access to the Developer Previews immediately. Release notes after the break.