I just installed the WHS App on my Android phone. If you have a Windows Home Server you should definitely check this out. It provides you some admin functionality, but the killer feature for me is remote access to my music and photo libraries from anywhere. With this I can I can virtually carry my 25 GBs of mp3s and 10 GBs of family photos wherever I go. Future planned features include video streaming as well. Fantastic!

If you have a Windows Phone 7 - this is the WHS app that should have shipped with the phone. One complaint I and many people have about Microsoft's consumer products is the lack of integration across their product lines, something that Apple does very well. Windows Phone 7 should have native support for WHS, Xbox, Windows Media Center, etc. And don't even get me started about the lack of support for Windows Media Center on WHS. But back to the task at hand, this app definitely fills part of that void.

AFAIK there is no iPhone version of this yet. There is a WHS app for iPhone from another developer, I think it is called WHS Mobile, but it doesn't look like it has been updated in a while and it doesn't look as nice as this one.