Tom's Hardware Guide posted a news story that an IE9 beta tester published the January 28 launch date via a tweet.

The RC and final version of the browser cannot be released too early as IE6/IE7/IE8 now account for only 57% of browser market share and IE8's adoption rate is slowing down, according to data released by Net Applications. What is especially noteworthy is the fact that IE9 RC may be released before Mozilla can get its Firefox 4 RC out of the gate. We are still waiting for Beta 9 and Beta 10 before the first RC can be released. At the current pace, the RC may not be released until late February.

  Internet Explorer 9 RC Coming January 28?