Are you talking about the Canon EF-S 10-22mm f/3.5-4.5 USM? That one would be a faster lens than the Sigma which is f/4-5.6. I would definitely go with the Canon EF-S in this case much better lens for a similar price.
Amazon.com: Canon EF-S 10-22mm f/3.5-4.5 USM SLR Lens for EOS Digital SLRs: Camera & Photo