Tracing in inkscape
http://www.youtube.com/watch?v=XLznZOpRpXM
http://www.youtube.com/watch?v=XLznZOpRpXM
http://www.youtube.com/watch?v=3wrnTdSqfSk
http://www.youtube.com/watch?v=s41_-qsmA7s
http://www.youtube.com/watch?v=3TXX10LdrhA
http://www.youtube.com/watch?v=Pyfw3FqlWmo
http://www.youtube.com/watch?v=cESqiwJcJ6Y
http://www.youtube.com/watch?v=qq7HsMvEVmU
http://www.youtube.com/watch?v=hauMpp6gBvQ
http://www.youtube.com/watch?v=
http://www.youtube.com/watch?v=s-kPg4vYKfk
http://www.youtube.com/watch?v=pa6a7oz7vEE
http://www.youtube.com/watch?v=8f011wdiW7g