These are from last summer's World cup. There are some great pictures (a link to all of them is below). However, take a look at these:

Look at the Australian player is positioned- hips square to her opponent, stick mirroring hers, and feet moving side-to-side

Now HERE'S a double team. Look at how freaked out the Canadian player looks. Both Scotticsh players are coming at her strong side, so she's going to have to either step back, roll to her weak side, or try and get rid of the ball.

The Scottish player has completely beaten her defender, by bringing the stick across her body (to protect it), and powering past. Check out the look on the defender's face: "Huh? Where'd she go????"
The links for MANY more pictures are:
http://www.lax.com/bimages/1461/1
http://www.lax.com/bimages/1462/1
http://www.lax.com/bimages/1463/1