I read User Stories Applied by mike cohn while i was in maui (don't make fun... i live this stuff) and when reading the part about estimating I thought:

 "I wonder if it might be better to take the peer pressure out of estimating by having the developers all face the same direction (towards the product owner/user proxy/user) and show their cards but not reveal to eachother what they estimated."

Then the scrum-master/PO can ask

"James, you're the highest estimate why did you choose that?"

and then

"Sally, you're the lowest estimate, why did you choose that?"

then have them re-bid without ever knowing what the other person bid. I personally haven't done estimating with a team yet so i'm interested to see if this is even necissary or warranted.

The reason being that, low bidders might come all the way up to the high bidder and the high bidder might go back down to the low bidder having known what their amounts were or other political reasons for 'following' someone elses estimate.

just a thought... jetlag is killer.