Google Tasks is similar to the Gmail Tasks widget recently introduced in the Labs, but it looks like it's not supposed to be officially released yet because this is displayed when you open Google Tasks FAQ:CONFIDENTIAL: This document is confidential. It contains sensitive information and is protected by the terms of your Trusted Tester NDA.
As this is not official yet, it could disappear and so may also happen to the data you enter in it (although i currently see my Gmail tasks data in Google Tasks which means they synchronize).
This new Google App appears to be for "Trusted Testers", which are people that test products before they officially appear, but Google Tasks is public when I try and I’m not a Trusted Tester.
And here's a funny thing: it says it was last updated May 13, 2008:
