And are available at MSDN downloads
As you can see the ECM Starter Kit is baked in to the MOSS SDK download, this also goes for the Office Forms Server SDK.
Go get it! (If you’re into SharePoint that is :))
Update: The SDK’s are supposed to install them self’s under %systemdrive%\2007 Office System Developer Resources and %systemdrive%\Windows SharePoint Services Developer Resources. But when I save the installers to my USB drive that has the drive letter G: and run them. Then there is where they get installed! Took me a while to find them 🙂