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arnt all redsnow's betas?
looks like this was announced only 6 hours ago?

True, they are mostly marked as beta, however this one in particular has been released only as a genuine beta test. The dev-team themselves have made it clear it is not for the general public and there are lots of issues. Most notably, bluetooth is disabled and many users are experiencing a respring when they try and play any type of media (video, music, etc.)
For most folks this kind of instability would be a deal breaker, hence the warnings.
It has been out for more than 6 hours, it's just you are not quoting the source...
 
Why would you bother unless you like headaches or being a beta tester:

Warning
If you depend on UltraSn0w unlock, STAY AWAY from iOS 4.2.1 and RedSn0w.
This is a beta tester program. It’s not a general release! Things can go very wrong, so please don’t even consider testing if you have pictures or other media on your device that you haven’t backed up!
The Bluetooth functionality is disabled for now.
 
If it's not on http://blog.iphone-dev.org/, then it doesn't exist.

The newest thing is the new unlock for 3G and 3GS phones..... 4.2.1 is still tethered.... :(

You are not quite correct. It HAS been released by the dev-team as a BETA. It's not on the front page of their blog because it is not for general public release yet. They made a public request for beta testers on Christmas Eve.

Also, for information, they released a fixed beta2 this morning which corrects the issues people were having with playing music and video files. Bluetooth remains disabled however.
 
This is true. XMAS eve they released the beta. You have to have a developers' build of the firmware or whatnot.
 
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