The hack was just released Thursday night (here) by the fellow who shot the demo video, and I have to say that it feels like it's still a work in progress. There wasn't much included and I haven't gotten anything to install (yet).
But the hack itself was easy to install, and it doesn't replace the original firmware, of course. All it does is modify the existing software and add a number of new apps. You get a new home screen, Cool Reader, a file manager, and a dictionary. It's also easy to switch back and forth between the 2 home screens (press the home button).
Unfortunately, I have not been able to install any apps yet. But to be fair I only tried for 5 or 10 minutes before writing this post. I was hoping to include a photo showing the Kindle app, but no. I'm also having trouble installing the Amazon Appstore.
The other problem I encountered was that my hacked T1 is still using the default browser, and it won't allow me to download install files. That means that I cannot simply browse a website like freeware lovers and download anything yet. But I'm still playing with it so that might change by the end of the day.
All in all, I am comfortable with suggesting that you install the hack. It looks relatively stable and it is reversible. Even if your attempt to install the hacked firmware ends badly, you should still be able to re-install the original.
I know I'm posting this without any amazing photos, but I wanted to get the news out as fast as possible. If more people try the hack then we'll figure out how to get around the quirks faster. You can find the instructions and a zip file with the hack here.