The Magic Lantern web-site has sufficient explanation of installing and using the firmware, but I thought I would lend a bit of personal insight to encourage you to try it.

Arguably, many of the features should have been included in the camera from the factory. It unlocks advanced features to Canon’s entry- and mid-level dSLRs (currently, T1i/500D, T2i/550D, T3i/600D, 50D, and 60D, and separately 5D Mk II), making them more usable. Magic Lantern adds capabilities that Canon doesn’t provide, relaxes unnecessary limits, and provides a bunch of convenience features that would take a lot of thought and pushing of buttons to configure. If I had known how easy this all was, I would have tried it years ago.

It can be easily bypassed, too, so you needn’t be afraid to try it out. It does not replace the camera’s built-in firmware, so you can use the camera as expected. I finally got to loading the Magic Lantern firmware onto my Canon T1i/500D and I am so excited! Magic Lantern is a firmware add-on for Canon dSLRs that enhances their use. T1i/500D Main LCD w/Magic Lantern running

Magic lantern canon t1i