Derailed!!

As for placement, I am still rather new to my clipless (about 600 miles or so), take with a grain of salt. Place them more to the from if you sprint alot(ie. more for MTBing and such) and more to the back if you spend lots of time in the seat (prob more what you are looking to do) I like mine in the middle but a touch to the front.
Word of advice... make sure you tighten the cleat bolts well! I did not and when I came to a stop in my driveway, I twist the foot and come to find I was on the ground.

Good luck and a few splills are bound to happen... make sure you try to master the system befor you ever leave home!