Well, actually, here they say don't flex your arms:http://www.bodybuilding.com/fun/drobson207.htm
Here's some that say flexed:http://www.weightrainer.net/maximum_potential.htmlhttp://www.essortment.com/all/measurementbod_rezs.htm
Here's one that says measure your arms any way you want:http://www.gain-weight-muscle-fast.com/body-tape-measurements.html
Here's one that says "cold" and implies a position of the arms that is associated with flexing, but frustratingly, doesn't mention flexing at all:http://www.t-nation.com/free_online_article/sports_body_training_performance/the_truth_about_bodybuilding_arm_measurements
Here's a thread where everyone quotes both:http://www.bodybuildingforyou.com/forums/bodybuilding-general-chat/33470-everyones-bicep-measurements.html
Helping people use the search box since 1999, I remain,
Your humble Google servant
PS Trigger, I just realized that your "OK I was just asking" might indicate you thought I was calling you a smart ass? If so, you parsed my post incorrectly. Think Henny Youngman, lame joke delivery, "is this mic on?" kinda thing. If not, then... as you were.
Sigh. One of the reasons I promised myself not to post at RJ anymore was nobody ever got my humor. I think I will go back into my hole now.