MSN Beta Search will only show you the first 500 results for a query. If you got less than 500 results you will see normally the double of the real number. Just add "count=100" at the end of URL and you will see the number slice by 50% or more.
First search : 61 results
Same search with 100 results : 26 results !!!
Same search at Google : 201 results (but 196 real pages)