Postcards are sweet, but they also kind of suck: If you're like us, you buy a ton and never send most of them, because of the hassle of trying to find a stamp and post office from wherever you are. Frog Design has created a far more elegant solution for iPhone users. Postcard Express, an iPhone app, lets you take geo-tagged snapshots and send them along to friends.

The app, which costs $3.99, has the sort of simple functionality that you'd expect from the powerhouse design firm where Yves Behar, Ross Lovegrove, and Tucker Viemeister all got their start. It piggybacks on top of pictures you take on iPhone. When you take a picture, you can then edit it using the Postcard Express's image-editor and add a personal note. The app then generates a mini-map in the upper righthand corner--where the stamp on a postcard would usually be--showing exactly where it was taken. Then you can send to any email address. Since the app is smart enough to send the postcard through email, there's no txt charges incurred and you can send basically as many as you want. (Though data-roaming charges will apply.)

This is Frog Design's first iPhone app, and presumable it won't be the last: Given all the in-house know-how among its 400 employees, apps could provide a pretty clever way of pulling in a bit of extra money. Hopefully, its competitors such as IDEO and Smart Design will also get on the game.

Meanwhile, on the travel front, the iPhone has already become almost an essential gadget for travelers, thanks to the magic of geolocation--there are literally hundreds of useful apps, but a few to check out in particular include Roadtrippr, the local guides by Pocket Places, Local Eats, and Lonely Planet City Guides.

[Via @Frogdesign]