Update: Looks like this was pushed early and not meant to be public. The beta has now been pulled and is no longer published.
Update 2: And now it is back again and you can download at will!
The Wunderlist beta app is now available on Windows Phone. Just last week we learned that the third version of Wunderlist would be arriving on Windows and Windows Phone 'soon.' Turns out that meant today, because you can download the beta right now.