There's some murmuring around the internet forums, with a (supposedly) leaked PowerPoint presentation regarding upcoming PSP accessories. While none of this information has been confirmed (Sony gave the usual "no comment"), we can compare this leaked information to what we already know.
First, Sony announced a new Skype headset which should arrive any time now. An updated Media Manager is certainly unknown, but also long overdue. A new travel case would also be welcomed, particularly for the new PSP-2000, which doesn't have a long line of accessories. The last bit involves the GPS coming to the United States, which has no official price at this time. It's all rumors and speculation, but it's all what you're waiting for. Maybe.