This is in public beta and available in the Windows Phone Store. http://windowsphone.com/s?appId=c2a60dc1-b299-441e-8b38-a7c2298471e2
This, I also have Path on iOS and it's a joy to use. I wish they have this on WP7.
Would be great to see Path for Windows Phone. Love the app for iOS. And I could definitely see a Metro inspired one for WP7/WP8 too.