Lobbying another shot in the cut-throat Internet Service Provider industry, MSN — which recently surpassed EarthLink to claim the number-two position — has launched a $50 million “switcher” ad campaign. The promotion offers new MSN customers three free months of access and guarantees monthly access fees will remain at US$21.95 until Jan. 1, 2003. Last week, America Online raised its monthly rates to $23.95