Good news for all those itching to get MOSS 2007 up and running -- Beta 2 will be upgradeable to RTM! This is a shift from earlier guidance, which recommended waiting until the Technical Refresh (end of summer/early fall).
That said, there is no "Go Live" licence for Beta 2, meaning it isn't recommended or supported to use Beta 2 in a production environment, unless it's plain to all involved that the instance exists for evaluation purposes. Why? To set appropriate expectations. Until the TR, the Technology Adopter Program (TAP) remains the only path to deploying MOSS 2007 for production. Or, you can bring in a great MS partner like ei to smooth the path.
But back to the good news. If Beta 2 will have a supported migration path, then there isn't stopping you from, say, trying it out at any given IS/IT shop for day-to-day evaluation. Given how superior WSS3 and MOSS are to their able predecessors, it's a free boost in productivity. It's like getting a free summer student, minus the post-hazing human rights hearing. From what I've seen, Beta 2 runs stable, the only hiccups you'll notice are the features that aren't quite code complete and/or optimized. And, it's summer. You have two months of relative peace before business goes back to overdrive in September. Take advantage of the lull and edumecate yourself forward. C'mon, you know you want to. Get the Beta.