I keep seeing this term thrown around a lot lately with all these beta releases and have had a hard time pinning down an exact definition of it, at least in layman speak anyway's. I feel a little stupid as if I should just know what it means; 'ya know a GO LIVE license, DUH'! Here is the only reference I have found (For Beta IIS 7) describing it in simple terms:

IIS 7.0 Go-Live FAQ

2. What exactly is a Go Live license? How is it different from a normal license?

A Go Live license is a license to use a Beta release of a Microsoft product in a live production environment, before the actual release of the product. It is important to also note that the Go Live license transfers from Microsoft to the licensee, liability for any unanticipated consequences, financial or otherwise, directly or indirectly caused by using the Beta technology before its official release.

Obviously license details could be different for each product but 2 things stand out in this description; 1) You're allowed to use it in production in its beta form and 2) MS is not liable for any problems the beta version may cause.

I wish there was more of a definitive source within MS for explaining licenses. I just went through this with an MSDN subscription purchase. It's almost impossible to find license details spelled out in one central place and in a way that's easy to understand without being a lawyer. And there are many licenses for the same product, so it's really hard to know what your getting into and which one is right for you.