Apple, the maker of iPods, iPhones and iPads, has overtaken the computer software giant Microsoft to become the worldÔÇÖs most valuable technology company. As of Wednesday, Wall Street valued Apple at $222.12 billion and Microsoft at $219.18 billion. The only American company valued higher is Exxon Mobil, which has a market capitalization of $278.64 billion. The shift marks a significant turnaround for the fortunes of Cupertino, California-based Apple, following a lengthy domination of the PC market by Redmond, Washington-based Microsoft.