We've looked at a few ways to take wireless photos with your iPhone and DSLR camera, but Matthew over at The iPhone Guru put together a different method that uses an infrared transmitter instead of Wi-Fi, removing a lot of the annoyances that come with the other options.
The video above will show you the entire process, but basically you need to build a DIY infrared trigger (which will cost you about $US2) that plugs into your iDevice's headphone port. You'll also need the DSLR.Bot app for iOS (which will cost you $6). The DSLR.Bot app will use you infrared trigger to send signals to your Canon or Nikon DSLR camera. It can even create a log with location data for tagging your photos.
If this is a project you want to try, be sure to check out the full instructions at the iPhone Guru.