Apple is no longer restricting Mac OS X betas to paying developers. Anyone with an Apple ID (which is, let’s face it, essentially every Apple user at this point) can now sign up for the OS X Beta Seed Program to test unreleased versions of the operating system. You have to agree to Apple’s OS X Beta Seed and Confidentiality Agreement and install the Beta Access Utility to view betas in the Mac App Store. After WWDC, we’ll see if this applies to major releases of OS X, or just minor updates.follow link
Springy Dock Tricks
If you drag a file and hover over Dock icons, various useful things happen which are similar to Finder springing. If it's a window, the window un-minimizes from the Dock. If it's a stack, the corresponding folder in the Finder opens. If it's the Finder, it brings the Finder to the foreground and opens a window if one doesn't exist already. But the coolest (and most hidden) springing trick is if you hover over an application and press the Space bar, the application comes to the foreground. This is great for things like grabbing a file from somewhere to drop into a Mail composition window that's otherwise hidden. Grab the file you want, hover over the Mail icon, press the Space bar, and Mail comes to the front for you to drop the file into the compose window. Be sure that Spring-Loaded Folders and Windows is enabled in the Finder Preferences window.
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Apple Opens Mac OS X Betas to All