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
Mac OS X Services in Snow Leopard
Mac OS X Services let one application supply its powers to another; for example, a Grab service helps TextEdit paste a screenshot into a document. Most users either don't know that Services exist, because they're in an obscure hierarchical menu (ApplicationName > Services), or they mostly don't use them because there are so many of them.
Snow Leopard makes it easier for the uninitiated to utilize this feature; only services appropriate to the current context appear. And in addition to the hierarchical menu, services are discoverable as custom contextual menu items - Control-click in a TextEdit document to access the Grab service, for instance.
In addition, the revamped Keyboard preference pane lets you manage services for the first time ever. You can enable and disable them, and even change their keyboard shortcuts.
Apple Opens Mac OS X Betas to All