There are days when I'm en route to work and then I remember — you were supposed to check flight prices for your big New Year's trip! Since flight prices are always going up and down, I either set up alerts or I remind myself to keep checking back to discount travel sites.
I already love using Kayak to compare flight prices, and now with its new and improved iPhone app, I can practically do all of the things on Kayak from my iPhone that I do on my computer. The Kayak app will also put all of your flight info, hotel confirmation, car rental bookings, maps, and other travel items into one itinerary — sort of like what TripIt does. I can definitely see this app making it to the top of my 2010 favorite iPhone app list.