Canon's latest professional DSLR camera, the EOS-1D Mark III, will begin shipping today in the U.S. and should arrive in some U.S. locations by tomorrow, according to Chuck Westfall, Director of Media and Customer Relationship at Canon USA. Early on, however, there may be not be enough cameras to meet demand until sometime in June. In addition to the EOS-1D Mark III, Canon is also shipping out the new Speedlite 580EX II flash unit. In Canada, the EOS-1D Mark III will begin distribution next month.