“This download installs Microsoft® Windows® Script containing Visual Basic® Script Edition (VBScript.) Version 5.7, JScript® Version 5.7, Windows Script Components, Windows Script Host 5.7, and Windows Script Runtime Version 5.7.”

Windows Script 5.7 for Windows 2000 (Yeah, I am surprised by this one myself…)
Windows Script 5.7 for Windows XP
Windows Script 5.7 for Windows Server 2003

I do not know what additional functionality this new version provides. I have not seen this updated on WSUS either. EDIT - It's worth noting the there is no Vista update, because Vista already have WSH 5.7.