Power Pack 1 will let people connect to Jetro servers with standard, unmodified Remote Desktop Connection clients. It will also add support for end-to-end session encryption and deeper Active Directory integration.
This marketing agreement is not to suggest that Microsoft will be ignoring Citrix. It's just one more sign that even Microsoft understands that Citrix isn't the only solution on the block anymore. This is a good move from Microsoft's standpoint. After all, Microsoft gets paid whether people use Citrix, Jetro, New Moon, or just plain Terminal Server.
On a completely unrelated note, Jetro has finally decided to make their support website and KBs available to the public.