Apparently Microsoft has (sort of) replaced the "Favorites" Windows explorer item with the Quick Access item. But I haven't been able to find a way to programmatically add folders to it (neither on Google not MSDN). Is there no way to do this yet?
There is a simple way to do it in powershell (at least) :
$o = new-object -com shell.application
$o.Namespace('c:\My Folder').Self.InvokeVerb("pintohome")
Hope it helps.