TAKTIK is an iPhone case meant for rugged use, so let your iPhone be as handy as a Leatherman on your next camping trip.  Of course, we don't recommend overloading on connectivity in the great outdoors, but an iPhone can help make the most of any trip with wildlife identification apps, useful utilities like flashlights and campsite reservation apps, trail maps, and trek loggers. We recently took ours to the Mississipi Palisades, and came back with a list of useful apps for the campsite.

All Trails (Free)
All Trails is pretty much what it sounds like. Get access to a database of more than 40,000 trail guides, whether biking, hiking or snowshoeing, based on your location.  It also has a GPS hike logger, allowing you to add your own favorite trails to the database. You don't need reception, but you will have to download relevant maps before you start trekking.

Knot Guide ($1.99 for pro version, free light version with less knots)
A great app for campsite improvising. This app is essentially an index to  any useful knot you can think of, from hitching to lashing to climbing. Each knot comes with a step-by-step photo guide to tying the knot correctly.

Camp Where ($4.99)
A comprehensive campground location and reservation app for public sites all over the US and Canada. Features include sorting by amenities, detailed campground maps, reservation phone numbers, elevation, and directions. Great for unplanned car camping trips or a change of plans.

LED Flashlight (Free)
Simple and straightforward LED flashlight app. This app takes advantage of the LED flash in the iPhone 4 to offer a powerful light when you need it.

Leaf Snap (Free)
A field guide to trees from researchers from Columbia University, the University of Maryland, and the Smithsonian Institution. Comes with visual recognition software that can identify a tree from photographs of its leaves. The app currently identifies Northeastern American tree species, but as they continue to develop the app, the guide will expand to the entire continental US.

Altitude+ ($1.99)
Nice little altitude app that displays your elevation (in feet or meters) above sea level on a sweet graphic that goes from under the sea to the stratosphere. Simple, no options, fast loading.

Gaia GPS  ($9.99)
Offline topo maps for backpacking off trail. Gaia GPS pulls from USGS databases in the United States and CloudMade topo and road maps all over the world. You can use it to log your treks and then display stats like average speed and altitude profiles.

Star Walk ($2.99)
Wonderful augmented star gazing app with a great price tag to boot. Point your iPhone at the sky and see all the heavenly bodies, visible to the eye or not. You can also identify and track constellations, satellites, and planets. Turn on Night Mode for a display just bright enough to see the information but not bright enough to detract from your night vision. And best of all, no internet connection is required.

Wild Edibles ($7.99 or a less comprehensive free version)
One of few foraging apps, with thorough identification aids, smart search filters, harvesting methods, and recipes. Beats a heavy field guide and great to have on the trail to help you find that bee balm, wild asparagus, or burdock root to make your campsite meal a great one. 

Sibley Bird ($19.99)
One of the best field guides to birds is now formatted for the palm of your hand. This app is a bit pricey, but worth it if you're a bird lover. Comprehensive list with a smart search function and hundreds of David Sibley's techinically accomplished and beautiful illustrations. Bonus: hear birdsongs and compare species for more accurate identification.