First up we have a video that explains the basics of MMO economics (gold sinks, inflation, soul binding, etc.) and ArenaNet's approach.
Next, we have a story by Ravious over at Kill Ten Rats, who explains why GW2's economic system will likely become the new standard in MMO's.
Read it Here.
Says Ravious:
I expect a much tighter profit margin during live when there will be greater market efficiency, but it is apparent that the trading post will easily create a game unto itself. I honestly could have spent the rest of beta just standing around finding inefficiencies and flipping items for people that devalued their time.