Update 2009/07/06:
Looks like the unresponsive “slide to unlock” issue may be due to the unlock instead of jailbreak. After Mac OS X version of purplera1n was released, i did the jailbreak again but stopped short of performing the unlock with ultrasn0w. That problem did not reoccur.

Two days ago, iPhone 3GS was jailbroken by geohot, who was the first known person to unlock the original iPhone two years ago. The jailbreak tool purplera1n was initially released on the Windows platform only. The tool was simple enough to use: open iTunes 8.2, connect iPhone to Windows-based computer, run purplera1n, and while in the purplera1n tool, click on “make it ra1n”. After a few reboots, iPhone is jailbroken. As part of the process, a iPhone app called freeze is installed. Running “freeze” will install Cydia, which can then be used to install ultrasn0w to unlock the iPhone.

I managed to jailbreak and unlock my 32-GB iPhone 3GS using the method described above. Initially, i had problem with WiFi not working. I realized that it may be due to the bossprefs tool that i had installed. Upon uninstalling bossprefs, my iPhone was able to regain its WiFi functionality. The next problem i found, which can be attributed to either the jailbreak or the unlock, or both, was the unresponsive “slide to unlock” button. At times, i would say almost all the time, it would take more than 3 or 4 seconds before the i could slide to unlock my iPhone. It became quite irritating that i abandoned the jailbreak and unlock and restored the 3.0 firmware on my iPhone.