The iPhone is an amazing device, and thanks to inventive app developers, it's a more powerful and impressive tool every year. I've had an iPhone for several years, and I'm still discovering features.
For instance, the iPhone can:
1. Work as a makeshift flashlight. The Flashlight app, available for free in the App store, allows you to use your iPhone's camera flash as a bright flashlight. If you have an older iPhone without a camera flash, there are also apps that display a clean white screen, which also makes for a workable flashlight.
2. Save you money at the supermarket. Apps like Coupons.com and Grocery IQ use your location to find coupons and deals at local stores.
3. Control how apps access your private info. If you don't want certain apps to access your location info, hit "Settings" and click "Location Services" to limit or grant access.
4. Help you lose weight. There are hundreds of weight and calorie apps, but my personal favorites are Calorie Count, which monitors your food intake, and Pushups Coach, which gradually builds you up to 100 pushups per day.
5. Help you sleep better. Check out apps like White Noise and Sleep Cycle to take advantage of your body's natural rhythms to get deeper, more fulfilling sleep.
6. Update your address book with Facebook phone numbers. In the Facebook App, tap "Friends" and then tap "Sync" in the upper right-hand corner to update your address book with your friends' Facebook info.
7. Stream podcasts. You can download podcasts on the iTunes store or use a service like Stitcher (free in the App Store) to stream Internet radio shows without taking up your iPhone's limited storage space.
8. Show more detailed battery information. Visit the iPhone's "Settings" menu and tap "General," then "Usage." You can turn on detailed battery usage information via this menu.
9. Show your per day usage information. From the same menu mentioned above, you can see the time you've spent since your iPhone's last full charge.
10. Scan documents. Apps like Genius Scan allow you to scan documents easily with your iPhone's high-quality back camera.
11. Use your own custom ringtones. If you have a chunk of audio that lasts 30 seconds or less, you can convert it to an AAC file in iTunes (check the rip settings). Rename its file extension to .M4R to turn it into a ringtone. For a more detailed explanation, visit Gigaom's blog.
12. Change your text autocorrect to Spanish. Hit the globe icon in any text window to switch your default language from English to Spanish or vice-versa.
13. Run credit cards. Free apps from services like Paypal and Square allow you to charge credit cards at your business. Square even offers a free swiper, which makes the process much easier.
14. Act as a music studio. The iPhone App FourTrack is one of many apps designed to use the iPhone's high-quality microphone to allow musicians to craft multi-layered demo recordings.
15. Play audio in mono. Visit the iPhone's Settings menu and tap "General," then "Accessibility" to turn the Mono Audio setting on or off.
16. Take panoramic photographs. Panorama, Photosynth and TourWrist all allow users to take stunning panoramic photographs with the iPhone's camera.
17. Tune your guitar. Check out apps like Cleartune for a remarkably accurate instrument tuner.
18. Magnify small text. In the "General" section of the iPhone's Settings menu, tap "Accessibility." Turn on "Zoom" and double-tap with three fingers to zoom in on anything on the iPhone's screen.
19. Sync calendars with your computer. Plug your iPhone into your computer and select the "Sync Calendars" setting in iTunes to sync your phone with your computer calendar.
20. Find directions by bus. After you look up a location in the Maps app, tap the bus icon before hitting "Route" to get directions via local bus routes.
21. Send voice memos to friends. If you're on a Wi-Fi connection, you can send a voice memo directly to a friend. Select the memo, then hit "Share" followed by "Message."
22. Enable custom vibrations. Visit the Settings menu again and tap "General" and "Accessibility" to set custom vibration patterns for each person in your contacts. This is useful if you're hard of hearing or if you spend a lot of time in environments where loud ringtones would be disruptive.
23. Help with home repair projects. Your iPhone can act as a decent level and plumb bob thanks to its built-in motion sensors. Check out the iHandy apps before tackling your next home project.
24. Get your finances in order. Check out Mint's excellent financial app to keep track of all of your credit card, loan and investment accounts at once.
25. Speed up text messaging with shortcuts. Visit the Settings menu and tap "General," then "Keyboards" to enable simple shortcuts for any phrase.
What are some of your favorite little-known iPhone secrets? Share them below.