The firmware update weighs in at 280MB and is available now through iTunes for the iPhone, iPhone 3G and iPhone 3GS.
Remember to have the latest version of iTunes (8.2.1) installed.
If you have a jailbroken and/or unlocked iPhone, you may still update to 3.0.1 and still have the ability to both jailbreak and unlock your device.
You may complete the update in iTunes to firmware 3.0.1 and then re-use redsn0w 0.8 to jailbreak your iPhone.Â Note however that when you run redsn0w 0.8, point redsn0w to the 3.0 firmware (make sure you have the right one for your device) instead of the 3.0.1 firmware when prompted for the firmware file.
After the jailbreak, you can still use ultrasn0w 0.9 to unlock your iPhone 3G/3GS (iPhone 2G users, your unlock is within redsn0w).
If you need further assistance and access to the 3.0 firmware files, you can use our Jailbreaking/Unlocking Guide here.