As the story of OS 4.0 unfolds, finally we have news that iPhone OS 4.0 is Jailbroken on 3GS! Before this it was only iPhone 3G, 2G and concerned G only devices which were able to get the jailbreak.
Although the process is not very simple and still under development, but it is now confirmed that 3GS devices will soon be able to Jailbreak the iPhone OS 4.0 with simpler procedures. Here is what iPhone developer, Kaatje, has to say about this development on her blog:
This is a work in progress but I thought I would share the results so far. Cydia still has some issues, many applications install but crash, some examples include mobileterminal, sbsettings, five icon dock. I did this only to hopefully motivate the developers to get their applications ready for 4.0 as it is coming very soon and the last thing we need in the community is to have repos full of broken apps! I accomplished this by patching asr, lockdownd, LLB, iBEC, IBSS, iBoot, kernelcache, MobileSafari, Services.plist, and fstab. The binaries were patched with IDA Pro and OxED and were then diffed against the original pwned files with bsdiff to create patch files. I then took the diff files and built a firmware bundle that I dropped into Pwnagetool and updated the cydia tree within Pwnagetool as well. Once this was done, I created a custom ipsw with Pwnagetool, unzipped it, applied a pwned LLB from a pwnagetool generated 3.1.3 ipsw, zipped it back up and restored to my device. At this time I am unable to get my T-Mobile NL sim to work so I downgraded back to 3.1.3 after playing around with 4.0 for a while. I look forward to the release and the official unlock from the Dev-Team. Many thanks to @p0sixninja for many hours patiently showing me the tricks and tips of jailbreaking 4.0b3 and then setting me out on my own to do beta 4. Without his tutelage, this would not have been possible
And here is the screenshot that has grasped our attention specifically: