George Hotz (aka geo or geohot) has updated purplera1n to make it work on Windows Vista and 7 including support for 64 bit systems.
purplera1n is a software tool which can jailbreak the new iPhone 3GS running on firmware version 3.0 to allow it to run apps from Cydia. Here are the acctual words from Hotz himself about the release info on purplera1n RC2:
Vista, Windows 7, International, 64-bit support
Less flakiness in the payload
Cydia tar cleaned up
Improved logging with slightly more useful errors
New kernel patches, codesign errors gone. Props posixninja
Added vm_map +x, passed vm_check
No winterboard yet, but now that ball is in Saurik’s court 🙂
Still in beta, use caution
Follow our guide here to jailbreak your iPhone 3GS running firmware 3.0 with purplera1n.