You can still get it. I just tried downloading it.
All you need to do is first download the latest version on your computer from the itunes store, so it is added to your apple id's 'purchased' app history (then delete it).
Then, when you try downloading the app from the app store on your ios 6 device, it will download the latest compatible version for iOS 6 (in this case, 2.2.3).
Hope that helps.