CardStar
Tired of carrying dozens of customer loyalty & rewards cards in your wallet? CardStar is the answer. Save & create scan-able bar codes which are stored in the app. When you approach the counter, launch the app and select the name of the merchant. Price: Free.
Update: I’ve tried using CardStar at my local grocery store and gym. Neither could scan the bar-code from my iPhone. 🙁
Gowalla
Not only does Gowalla do all of the cool stuff the other location-based apps do, it makes it fun by giving you stamps & rewards for each place you visit. Gowalla has one of the most polished iPhone interfaces I’ve seen. You can also use it to update your Facebook and/or Twitter status. Price: Free.
iFitness
Track individual exercises & workouts at the gym. iFitness also has a number of built-in workout programs. The application keeps track of the exercise, repetitions & weight. It also keeps historical data to allow you to track your workouts over time. Price: $1.99.
Tweetie
If you love Twitter, don’t be caught without Tweetie. The Tweetie iPhone app packs more features than the Mac equivalent, including: location-based/geo-enabled tweets, ability to quickly look up user names, shrink URL’s and add or snap photos with a few taps. You can also use Tweetie for multiple Twitter accounts. Price: $2.99.