iH8sn0w is all set to release to updated version of Sn0wbreeze named Sn0wbreeze 1.6 to jailbreak iOS 4.0, and it will be available for download soon! Sn0wbreeze is a famous jailbreak tool and it works similar to Dev-Team's PwnageTool, it's used to create custom .ipsw firmware files. PwnageTool is for Mac users, while Sn0wbreeze is for Windows users. Sn0wbreeze 1.6 will be fully capable of jailbreaking iPhone 3G/3GS and iPhone Touch 2G on iOS 4.
There is no word about release the date, but from the following screenshots shared by iH8sn0w, we can comprehend that it's almost ready and should be available is next couple of weeks.
Funkeyspacemonkey has shared a demo video of the tool for iOS 4, here it is.
[Video via funkyspacemonkey]
We'll share the tool as soon as it's released, keep visiting for updates! In the mean, you can use following tools to jailbreak/unlock iOS 4.
Update 1: Guide to Jailbreak iOS 4.0 with PwnageTool 4.0
Update 2: Guide to Jailbreak iOS 4.0 with Redsn0w 0.9.5b5-4
Update 3: Sn0wbreeze v1.7 - Jailbreak iOS 4 on iPhone 3GS (New Bootrom) / iPod Touch 2G (MC Models) & iPod Touch 3G