For either Mac OS X or Windows, this build takes advantage of geohot's recent limera1n exploit (the same used by greenpois0n and PwnageTool), leaving the SHAtter exploit to (hopefully) be saved for another day, according to the Dev-Team Blog.
The Dev-Team has also incorporated two additional extras to this build. Firstly, "...custom bootlogos for iPhone3G/iPhone3GS/iPod2G users (with qualifying bootroms)." And secondly, "an option that implements the 'DFU' button in PwnageTool. This button (which you can use from Windows) lets you prepare your device for a custom DFU. Even if you're purely a Windows user, you can get a trusted friend to run PwnageTool over your IPSW to create a custom IPSW. You can now install that custom IPSW on your own Windows box, after you run this redsn0w version."
For the download and further details, check out the Dev-Team's announcement post.
If you've gone and done the deed, let us know how it's working out for you in the comments below.