Apple released the iPhone OS 3.0.1 firmware update the other day to fix an SMS security flaw. This has rendered purplera1n useless, and creator Geohot has abandoned the project for now. That being said, redsn0w from the iPhone Dev-Team still works.
There's one thing to look out for when using redsn0w to jailbreak 3.0.1. After updating to the official 3.0.1 through iTunes, running redsn0w will ask for the IPSW file to use for jailbreaking. Select the 3.0 IPSW, not the 3.0.1 version you just installed. For owners of the iPhone 3GS or a newer 3G, you may not already have this file.
If your iPhone came with firmware 3.0 installed, you may have to download the file (iPhone2,1_3.0_7A341_Restore.ipsw) using iTunes before proceeding. Dev-Team has also stated that 3.0.1 does not change the baseband, therefore ultrasn0w will still work to unlock the jailbroken iPhone.
Apple has only changed code in firmware 3.0.1 to fix the SMS vulnerability, this is why redsn0w 0.8 and ultrasn0w 0.9 still work. The coming changes to redsn0w are simply cosmetic. From the Dev-Team:We’ll at some point fix redsn0w to recognize both 3.0 and 3.0.1 IPSW’s, but really that’s the only change that would be made to it. Everything else would be identical, so there’s no need to wait for the “proper” version that recognizes the 3.0.1 IPSW as valid.
As for purplera1n, Geohot weighed in on his blog:
Newest iPhone FAQs
Apple changed the kernel from 3.0 to 3.0.1, and I patch the kernel in a very specific spot. I code to make things simple, hacky, and fast. Dev codes to make things proper, slow, and complicated; redsn0w works OOTB. I could imagine a tool that takes the best of both worlds. No reason you need to push buttons or give the jailbreak program an ipsw; you can still write something generic that'll work on every device and version. And be fast. But I'm too lazy to write it.