I have bought this motor Shield:
http://www.ebay.com/itm/Motor-Drive-Shield-Expansion-Board-L293D-For-Arduino-Duemilanove-Mega-UNO-/290700252856?pt=LH_DefaultDomain_0&hash=item43af15d6b8#ht_3804wt_1396
But it is different than the one in the arduino web site, the motor shield. And the name says Motor Drive Shield Expansion Board L293D.
Do you know where can I find the documentation for that motor shield? I tried but couldn't..