You may not know, but does the Dept. of Justice announcing they won't challenge state medical marijuana laws have any effect on pre-employment drug testing? Why or why not? Most employers seem to be moving away from it, in my experience.
Things are a bit different in the software world, where employers are moving away from drug testing because they need all the talent they can get. It turns out some potheads are actually pretty productive members of society if you give them a chance.