IBM's a huge place, and I don't feel comfortable saying "we announced" for thinks like zEnterprise, but I do say it for smaller projects in which I was intimately involved. That's a bit important to keep in mind, because when I speculate about some of the things that zEnterprise could do, keep in mind that it really is just my guesses.
Z is all about workload -- the kind of processing you're doing -- and keeping it flowing through the system with no disruption or downtime. zEnterprise seems like it could bring the promise of that infrastructure to all sorts of systems. Like, imagine some Redmond Server on x86 blades, with Z style failover, load management, and so on. Might make that system reliable enough for enterprise use. :) Or truly "unbreakable" x86 Solaris. :)