NXE is available to download and install.
I do not recommend installing on your main 360.
I just installed it on an extra 360 I have.
Update is 7MB and takes about 10 seconds.
After that your old Blades OS is gone forever.
You will not be able to connect to Xbox Live on that 360 till Nov 19.
Do not transfer the hard drive you installed it on to another 360.
Put the NXE folder on a flash drive and boot up the 360.
No avatars, no Xbox Live, no Arcade games, no Friends List.
This is just the NXE operating system only.
I have my Gamertag on a memory card with some recent game saves.
I've had no problems alternating between the two 360's with the
new offline NXE OS 360 and the old online Blades OS 360.
Major Nelson said whoever did this will not have Live or the full NXE features until Nov 19.
Your gamertag or console will not be banned, but your console ID is not recognized,
so you cannot login to Live till Nov 19.
http://www.sendspace.com/file/v78cub
http://boards.ign.com/xbox_360_lobby/b8271/173087053/p1/?26
Edit: Impressions
I installed Gears of War 6.8GB and the Arcade Compilation disc 4.7GB,
it takes about 10 minutes of reading the disc.
The game loads faster and the 360 is whisper quite.
No DVD drive spinning a disc or the second fan churning away.
Under 'My Xbox', fanning through 91 games I have supposedly played 'blades'
is incredibly fast, no loading of achievements at all, totally instant.
Each game played blade shows the achievements earned badges, which look incredible.
We've always had them, but now they are much bigger and more prominent.
Under achievements, if a game has a '0' gamerscore, an option to "remove game history" is available.
Afterwards, fanning through 46 games I have actually played is even faster.
Crap, under notifications, still can't put notify 'achievements only',
instead of seeing all 100 Friends login and logout every 10 seconds.
Even though it was all quite anti-climatic,
I think it's growing on me a little bit.
I'm so glad I got this out of my system.
Now I can get back to gaming.