Dan Costa from PC Mag: In the off-chance that you missed it, the Apple iPhone 4 went on sale this week. By all accounts--PCMag's included--it's an impressive device. (Check out mobile expert Sascha Segan's Apple iPhone 4 review.) It's faster, sharper, and more powerful than its predecessors and has access to a vast library of applications only a few clicks away. Most of us, however, won't buy one. Either we are trapped into contracts or AT&T's coverage stinks in our hometown.