Our reporter Alli Flowers was at CTIA 2008 this week, and here is a video review of the newly announced Windows Mobile 6.1:
In this video you can see among others: home screen improvements, copy and paste now also in devices without touch-scren, usability improvements in e-mail inbox, threaded text messaging, full web browsing with support for Flash (including support for regular, non-mobile, YouTube site).

Now also transcript of Robbie Bach's keynote at CTIA 2008 is available here and Windows Mobile 6.1 was an important part of it:
So, that leads us to the next innovation we want to announce, which today is Windows Mobile 6.1. Now, Windows Mobile 6.1 is a very important release for us on the operating system level. It does a number of things. Primarily it's designed to make the phone simpler and easier to use when you're using for voice, data, communications, and entertainment, because that's actually a lot of breadth to span, and we need to continually work to make sure users can get access to the scenarios they want to complete.
So, that means a new home screen, the ability to customize that home screen, to improve navigation on that home screen so that people can get where they want quickly and easily.
It includes a new Web experience on Windows Mobile 6.1 that gives you the full desktop experience you might expect, so that you can browse Web sites whether they've been optimized for mobile phones or not, and you can reach out and interact with those Web sites in a very rich and deep way. And it certainly provides a platform for entertainment experiences that will be much richer than anything we've had before.

Source: msmobiles.com

Taimur Asad (The Microsoft "Wow" Blog!)