B&H has the Sigma 17-50mm f/2.8 EX DC OS HSM lens for $369 (reg. $669) along with 4% rewards. This is for APS-C format Canon and Nikon DSLRs. Check it out here at B&H Photo.
Sigma 17-50mm f/2.8 EX DC OS HSM Lens Now Available
Sigma HQ is reporting that its new 17-50mm f/2.8 EX DC OS HSM lens is now available for Canon DSLRs using APS-C sensors (like the Rebel T2i, Canon 7D and Canon 50D). Nikon and other mount versions of this 17-50mm lens should also be available soon.
The lens carries a retail price tag of $980. Check availability at B&H Photo / Adorama / Amazon.com