iH8Sn0w has released a beta of Sn0wbreeze a software utility which jailbreaks the iPod Touch 1G, 2G and iPhone 2G, 3G, and 3G[S](old bootrom & non MC).
The software requires Windows XP, Vista, 7 (32 or 64 bit), .NET Framework 3.5, and 256mb of RAM to run.
Sn0wbreeze is similar to PwnageTool for Mac. It will allow you to create custom ipsws which can be built to include Cydia applications and personalized boot logos.
Currently, the beta only supports SIMPLE mode. SIMPLE mode only provides a jailbroken and activated ipsw. iH8Sn0w has announced that EXPERT mode will be completed by Monday at which time a final version of the application will be released.
At this time BlackRa1n is still recommended for Windows users due to its ease of use. Once the final version of Sn0wbreeze is released we will post a tutorial for those looking to build their own custom ipsws.
[Important Update]: It has come to our attention that Sn0wbreeze may be using work from the iPhone Dev Team without credit and may be breaking the xpwn license. Apparently Sn0wbreeze also embeds the bootloaders required for jailbreak which is illegal. Until these issues are resolved it may be prudent to wait for the release of RedSn0w or PwnageTool for Windows.