Top 10 IT headlines for May 20: Developers slow to build on Vista, hosted Exchange ramps up, more muni Wi-Fi closures

Top IT headlines for Tuesday, May 20, 2008: Developers are dragging their feet in building software for Windows Vista, more municipal Wi-Fi networks are folding, Microsoft predicts that it will host half of Exchange inboxes within five years, Apple is dominating the over-$1,000-computer market, and more.