Unfortunately Apple doesn't have a solution to this problem for the mini DisplayPort RGB adapters. I noticed this in October. This is the solution:
Get the miniDisplayPort-> VGA adapter, VGA cable (the projector should already have this), RCA audio cable (plugs into laptop's sound card/headphone port and outputs to the red and white audio cables). That's the cheapest solution for a projector. There used to be a composite/s-video adapter for the previous macbooks but they don't make them for the new ones.
If you want to do it on a TV that doesn't have VGA/DVI input then get:
miniDisplayPort-> VGA adapter
VGA cable
RCA audio cable
Video Converter box (converts an incoming video signal to a different output video signal like composite, component, HDMI (don't quote me on that), VGA and/or DVI depending on the converter model)
Composite cable - yellow video cable
Hope that helps mate.