I don't have an iphone myself, but my bf does & he would probably use it. as i know he'd like to lose some weight & i strongly beleive in journaling your food.
I have an iPod touch, and a FitDay app would be great. I'd love it if it would let you share some of your info (like reaching a goal, your daily workout, etc.) through Twitter or Facebook somehow.
I've been exploring the various apps available for the iPhone. As much as I would like to be keeping track on the iPhone, none of the apps available match the functionality of FitDay and FitDay PC. I would love to see a FitDay app. Based on what I've seen out there, I would expect you could pass the others easily.
Please put your announcement of the new app on your log in page so we can get the word right away! This would be a great addition to your suit of tools.