http://www.northlight-images.co.uk/article_pages/install_canon_software.html#mac_canon_software

First impressions.

• For low light go to P mode and pick the highest ISO possible.  Go to Shooting Settings Display and then hit the ISO button, pick 6400.  Night shots start looking good.
• Also try the continuous drive mode (page 70 of the manual)
• http://www.t2iforum.com/
• http://michaelthementor.com/store/index.php?main_page=product_info&cPath=1&products_id=19