if you get hold of one of the crew at Club Vass (Dahab), they can pre-book it for you for an agreed rate. We paid the equivalent of £10 for what it is an hour journey in a minibus with more gear than a windsurf shop, but do tip and you'll be picked up on time and returned to the airport in good time. Also, when you hand your gear in at the airport, drop the baggage guys a tip and your gear won't get trashed!

I'd imagine the other centres would do the same thing, too. Have a great trip and check out the snorkelling/diving if you get the chance.