Maybe a Dumb question - T2i
the t2i (as a compact model) doesn't have enough wheels/dials to simultaneously perform all of the functions you ask. the quickest way to allow the dial to change aperture without a simultaneous button press is to set the camera to Av mode.
the 60d is the next mid-size model in the canon lineup that has 2 dials that can do what you ask in Manual mode. the top dial by the shutter button will change shutter speed. the circle dial near the thumb will change aperture.
the 60d and t2i share the same sensor (essentially) but the 60d has a moving LCD, faster continuous drive, is weather-sealed, etc.
hope you find what you're looking for ...
Im really sorry if this a dumb question, Im new to the Canon brand.... On the T2i- In Full MANUEL mode, how do I get the camera to change the aperture without pushing the "Av" button and turning the dial? Right now when I move the dial it changes the shutter speed, I want the camera to change the the aperture just by turning the dial and not pushing the "Av" button in manuel mode....
Thanks in advance!