How do you spot the left side pedal on egg beater pedals?
This is from the Crank Brothers pdf available on their site or in the package:


  Eggbeater pedals have either a 6mm Hex, an 8mm Hex, and/or 15mm wrench flats.  Note that the right pedal has a 
  standard right-handed thread and the left pedal has a left-handed thread.  For identification, left pedal has a small 
  “L” on the spindle or a small groove around the spindle flange.  The right pedal has a small "R" stamped in the 
  spindle or no special markings.


In my case there was no "L" on the spindle, but there is a small groove around  the left spindle flange.

The link: http://www.crankbrothers.com/support/product_documentation/instructions_eggbeater.pdf