Apple's Phil Schiller has joined Scott Forstall (though not Steve Jobs) over on Twitter -- he now has a verified account to tweet from, and is following a few celebrity and official company accounts so far. The account's actually been around for a while (Schiller tweeted from France while there and mentioned 500 million app downloads when it was announced last January), but only recently got verified, which means there's one more official Apple voice on the networking service.
It's strange that Apple still doesn't have a real official presence on Twitter -- Schiller follows an account called @AppleIncNews, but it appears to be a simple RSS feed of Apple website news, and it's not verified by Twitter as official at all. There are certainly plenty of fake Steve Jobs accounts, but none of those have been verified either. Especially since Steve seems so easygoing with his Stevemails, you think Twitter would be a perfect place for him to interface directly with the Apple community.
But so far, all we've got is Forstall and Schiller, and neither of them seem very forthcoming about interacting with the community of Apple fans online.