As you Windows Phone users know, YNAB isn't working on an official Windows Phone client.
However, Tim, a long-time YNAB user, has been working on an unofficial client. It's called Divvy and is available on the Windows App Store.
Here's a quick rundown, along with some screenshots of this pretty slick little app.
The app is read-only, with offline support for adding transactions. You can mark categories as favorites, for quick checking of a category balance, and view your account balances and underlying transactions with a few taps.
The Windows Live Tile feature is pretty cool. I'm a little jealous of that (okay, a lot). Check out these screenshots, or hop over to the app store and grab it (it's free) so you can get your YNAB data on your Windows Phone!
Update 4/25/14: You can support Tim's development efforts through the in-app purchases, which allow you to: remove ads, and the "pro" option enables live tiles, offline transactions, and any other future pro upgrades.
As this is an unofficial YNAB app, we can't offer support directly here. However, you can contact Tim, the developer directly within the app. He's been super responsive with beta testers, and is excited to hear feedback and see this application evolve.
Congrats to Tim for shipping!