Celeste is a new jailbreak app that allows you to send and receive files using your iPhone, iPad or iPod Touch with any Bluetooth-transfer capable device. You can transfer songs, photos, videos, contacts, and more, with the feature pretty well-integrated into your iOS apps; you might even forget it wasn't there originally.
It's good to know about this option, since old file transfer apps like iBlueNova haven't been upgraded since iOS 3.x. So if you're interested, it's available now on Cydia for $9.99 via the ModMyi repo. Remember, it requires your device to be running iOS 4.2 or higher. [Redmond Pie]