In case you hadn't heard, NYC start-up MeetMoi has a new spin-off called Xtify, which according to their VP of Products Gil Barron, is a platform for enabling Web developers to include Location in applications. From what I can tell, Xtify takes over where Fire Eagle fell short by including a data collection client for most mobile OSs. Once deployed, the Xtify client periodically pushes location to Xtify's server, where they then make the data available via a RESTful web service with some sort of authentication and authorization I presume. Data sources include GPS, WiFi (by Skyhook and Navizon) and Cell-ID - Gil says the later comes from carriers and a "proprietary database" Xtify has built.