In camera metering help please!

[ANDS!]

I've already shot in manual, Av & Tv. I was just curious why when I do shoot in program that they're consistantly under exposing.

Because Programmed is just a step above AUTO, and AUTO might consistently give you poorly exposed photographs, because the camera is "playing it safe". It sucks, but it is what it is. Of course your camera shouldn't be fooled THAT often.