The install script for the SDK is located at repository.maemo.org, which is currently down due to the migration (see http://talk.maemo.org/showthread.php?t=88659). There are some temporary mirrors available (see http://talk.maemo.org/showthread.php?t=88707), but I think it's better to wait in this case (that's what I'm doing after I upgraded my distro without backing up my scratchbox stuff ), as to install and use the SDK, you would need to download many packages, which will place an unfair burden on those hosting the mirrors.