Makes you wonder, doesn't it? Throughout this thread I've seen derogatory comments about "overseas" talent, which is to be avoided like plague.
Are the developers in USA really 10x more effective than in Asia/poorer parts of Europe, to warrant the 10x higher salaries? To me the answer is obviously not (I live in Eastern Europe), but perhaps there is some magical quality one acquires upon moving to the US :-)
Once remote, does it really matter that much whether the other party lives on the same continent? http://37signals.com/svn/posts/3064-stop-whining-and-start-h...
EDIT: Obviously charge western rates if you can :) My point is it's hard to justify the imbalance of market value that you mention, in case of IT freelancing.