Your LCD is probably not calibrated correctly. It's probably set to a really high brightness setting. If you're using the camera LCD, try knocking it down on brightness, using that little gauge on the bottom so that it tells you where the exposure is. I usually like to expose faces around +1. Maybe right in the middle works too but it depends on the lighting in the frame.
I'm assuming the T2i has that. I'm using the 7D but I'm sure it has something like that.
Another option is to get an external LCD like the Ikan VX9 and calibrate that so what you're seeing is exactly what you're getting. That's the best option.