The redsn0w beta has been updated for 4.0GM on iPhone 3G and iPod touch 2G. Multitasking and homescreen wallpaper are turned on by default (Apple doesn’t normally allow this on these 2 devices). You can deselect these features if you choose.
Just like the other betas, this one intentionally doesn’t “hactivate” the iPhone. Please wait for Apple’s public release of 4.0 for that part of it.
YOU SHOULD STAY CLEAR OF THIS BETA SOFTWARE IF YOU RELY ON A CARRIER UNLOCK. That’s because the beta redsn0w works only if your device has already been upgraded to the stock 4.0beta1/beta4/GM IPSW from Apple, which contains a baseband update. If you installed that IPSW, you’ve already lost the carrier unlock until the next planned release of ultrasn0w and blacksn0w.
Get redsn0w for Windows here.If you don’t know how to use redsn0w, follow our Mac tutorial (exactly same process )