Expedia is rolling out an iPhone app that allows travelers to research flights and manage their itineraries. The app, called TripAssist, gives Expedia users the opportunity to sync their online itineraries or upload itineraries from flights and accommodations booked elsewhere. “Regarding marketing support, Expedia will primarily leverage our social communities using tweets, posts and video production specifically geared towards the web, as well as outreach to the blogosphere,” said Adam Anderson, director of public relations at Expedia, Bellevue, WA.