Yes you can connect the external drive to both PC's.
Some USB Y cables use a standard USB and some use a Mini USB connection on the single end.
http://www.newegg.com/Product/Produ...der=BESTMATCH&Description=USB+Y+Cable&x=0&y=0
Some USB Y cables use a standard USB and some use a Mini USB connection on the single end.
http://www.newegg.com/Product/Produ...der=BESTMATCH&Description=USB+Y+Cable&x=0&y=0