Stop Press! iOS6 and Olloclip have made this 'Ible out of date but it's here as a bit of history now.
There's no wide-angle lens on an iPhone, but that won't stop you from making wide shots. There's an app called AutoStitch (from Cloudburst Research) which gives good results if you learn how to use it effectively.
Here's how I make pictures like this with it:
Step 1: Building Blocks
Digital panoramas are made by joining separate pictures together. The software looks for the best match between similar parts of different images. If you give it exactly the right information, it works really well.
Start by framing your first shot at one side of the area you want to cover. Let's say you want to work from left to right across a landscape scene. Take your first shot. Make a note of a key item in the picture. Move your phone camera across to the right a little way to take in some more of the scene. It should look a little different -- but not too different, so make sure you include the same key item in it. You are aiming to give the app plenty of overlap to work on. Continue the process, changing your key items as you go. Sharp, clear edges work best as places where joins will work well.
I've shown my "key items" in the seven separate pictures here by adding image notes for you to read:
Step 2: Second Shot
Notice the re-framing across the scene to the right but the second shot still includes the key items from the first shot.
Step 3: Third Shot
Keep moving across the scene, looking for suitable overlapping areas for good joins.
Step 4: Shot 4
Just keep going, thinking about good clear overlaps.
Step 5: Shot 5
Continue as before.
Step 6: Shot 6
Repeat the technique.
Step 7: Shot 7
The last one in this series.
Step 8: AutoStitch
Use the AutoStitch app to pull in all the shots in your series. Then simply ask it to stitch them together.
Step 9: The Raw Output
AutoStitch may surprise you with the way it patches your pictures togeher. Some photographers like this as an art effect, others don't. It's a personal choice, so I've carried on this instructable and shown you the cropped version in the next step.
Step 10: Crop
Autostitch will automatically crop the final image into the best rectangle for you if you wish.
Step 11: Black and White
I wanted a crisp snow scene in black and white, so it's time to say thanks and goodbye to AutoStitch and use Photogene to get rid of the colour. Or you can use your own favourite digital imaging app or on-line service instead.
Step 12: Brightness & Contrast
Most snow scenes look dull from auto-exposure sytems like that in the iPhone's camera. I like my shots to "pop" a bit more, so I run them through an app called Perfectly Clear (from Athentech Imaging) as the final stage in my workflow.