Plenty of Facebook phones around right now, from the dedicated ones such as the HTC ChaCha and Salsa to the ones with added Facebook functionality, like the Facebook inside Xperia handsets. But the Vodafone 555 Blue offers something different, this is the world's first Facebook phone that is prepay only.Designed in conjunction with Facebook and with a dedicated Facebook button, the 555 Blue is classic prepay fodder, offering the functionality but without the headline-grabbing features. So we're talking a QWERTY keypad, 2.4-inch display, and a two-megapixel camera with flash. There's also a music player, which is good with your MP3s, WMAs and AACs, 40MB of on-board storage, SD card support (up to 16GB), an FM radio and Bluetooth 2.1. So what about this Facebook stuff?Well, according to Pocket-lint, messages from your Facebook friends will appear in your inbox alongside emails, with updates automatically loading in the background, so you don't miss a thing. Not too quickly though, just 2.5G connectivity here. Internet browsing is covered by the Opera Mini 5 web browser, should you fancy going outside of the Facebook arena.No pricing as yet, but we would guess 'modest' and hitting the shelves in good time for Christmas.