Tripit is without question one of my favorite services. I signed up for Tripit Pro earlier this year and it has paid for itself many times over. I get text messages when I land telling me of gate changes. I get flight delay updates before others. The point tracking system is simply amazing.
With all that said, I am basically shilling for Tripit right now. They have lowered their annual price to $49 and have sent a discount code to distribute to friends for $5 off. If you travel at all on a frequent basis, I have to say that you will be amazed by this service. If you are interested, the discount link is here.