[greg_mitch]

I have owned a Nest Learning Thermostat for some time, but have been frustrated at the lack of Windows Phone and Windows 8 (metro) apps. I have tweeted to @Nest and they directed me to a forum post on their website. There are several comments there in support of developing an app. Nest says that they do not comment on anything that is still being developed, but they are swayed by commentary on their forums.
I don't want to flood their forum with Windows Phone or Windows 8 fanboys, but if you seriously are interested in Nest or already own a Nest Tstat and would love to have a dedicated app, please go to the forum post and add your support by commenting on the suggestion.
https://community.nest.com/ideas/1014#
At the very least, they could release a public API so 3rd party developers could fill in the gap.

[larspassic]

I love the idea of Nest, but my wife and I agree that without an app, it is just an expensive thermostat. If they made a Windows Phone / Windows 8 app, we would be buyers.

[avmba]

You might be interested in this then ;)

Nest Thermostat | Windows Phone Apps+Games Store (United States)

[220SeaChaser]

Just downloaded the third party version. Works great except that there is no option to change from heating to cooling. I'm sure this can be included in a future update, provided Nest doesn't shut down the API on it first.