A plethora of resources exist today for organizing, planning, booking and just generally making travel more convenient. I've tried to capture some of the better systems by category in the text below: Travel Booking Systems: TripSync - TripSync is a booking system for small to medium sized businesses. This application lets a business book and manage flight, rental car, and hotel reservations. TripSync also allows for administrators to be assigned to an account which makes it possible to book travel for several people within a company.
TripHub - Founded by ex-Expedia and Microsoft executives, TripHub allows users to coordinate group their travel plans. If you are in need of bringing order to chaos for large travel groups then this is the service for you.
Travel Organizers: TripIt - Founded by some ex-Hotwire folks, TripIp is a travel organizer that helps do-it-yourselfers manage their travel plans. This service is great because you can forward your travel via email to TripIt. They turn around and automatically create a master itinerary which includes information like weather, maps, driving directions and destination information.
Trip Planning Tools: FareCast - What a great service. FareCast helps you predict if airfares will increase or decrease before the flight date. Other Trip Planning Tools Include: Real Travel Yahoo! Travel TripUp Trip Memories: EveryTrail - This application allows you to upload GPS data recorded during a trip and add photos, comments and notes. Google Picasa - Now with geo-tagging capabilities as well.