Canon has released DPP 3.8.1 on its website. As I understand it, not only does it add support for the T2i/550D, but it also adds a rotate feature.

If you shoot RAW with any Canon camera, this could be a worthwhile download.

Canon EOS 5D Mark II Digital SLR Camera (http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&tabact=SupportDetailTabAct&fcategoryid=215&modelid=17662#DownloadDetailAct)