500px (www.500px.com) has hinted at an official app for Windows Phone in the works, though no ETA was confirmed. An official app is already available for Windows 8, but if you're rocking a Windows Phone, there are only third party alternatives while we wait for the service to launch an official solution.
The unofficial apps aren't bad by any means, but it's always better to have official support for the platform. Here's the Twitter conversation where a member of the social team for 500px teased that a Windows Phone app is on the way. While it's no app announcement, it's safe to say there's something in the pipeline.
But what can you do in the meantime? As noted above, there are some really decent unofficial solutions already available on the store. Two of our favourites are my500px and Shoopix. We strongly recommend you check them out.
Source: WP-Seven.ru (Russian)