TORONTO (Reuters) - The Canadian dollar weakened on Friday versus its U.S. counterpart, as commodity prices and equity markets retreated ahead of a key reading of economic growth in the United States, Canada's largest trading partner. At 8:15 a.m. the Canadian dollar was at C$0.9968 to the greenback, or $1.0032, compared with C$0.9939, or $1.0061, at Thursday's North American close. The currency weakened into that close after disappointing financial results from technology giant Apple Inc and data showing Spanish unemployment hit a record 25 percent in the third quarter. ...