iPhone dev team are known to be working on iPhone 4 jailbreak & unlock however Redsn0w 0.9.5, the tool released by iPhone dev team can only jailbreak iPhone 3G iOS 4.0 & iPod Touch 2G 4.0. Whereas Pwnagetool 4.0.1 can jailbreak iPhone 3GS old bootrom which is only for Mac OS.
iH8sn0w the guy behind Sn0wbreeze with which you can jailbreak iOS 4.0 on iPhone 3GS/iPhone 3G & iPod Touch 2G non-mc model on Windows also he was the first one to release tethered jailbreak iOS 4.0 on iPhone 3GS new bootrom and now he has released updated Sn0wbreeze 1.7 to lets you to jailbreak iPod Touch 3G only if you have SHSH blobs saved for iPod Touch 3G 3.1.2.
Sn0wbreeze 1.7

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