We use iPhones here for business because O2 make it very easy and despite originally being Microsoft bods here, there is truly nothing like the iPhone when it comes to a competent mobile business device.
Anyway we live and breathe rugged here, so even our iPhones are rugged and I always get asked everywhere I go what the yellow and black case is on my device!
It’s an Otterbox Defender and they sell these for a range of other devices too and we can even get them made up if required on larger orders so always ask if your device is semi or non rugged.
They sell for the iPhone 3G, 3GS and the range has just become available for the 4G and iPad too. They come in 2 or 3 forms ranging in bulkiness and of course ruggedness!
Get in touch if you need any more help.
The Rugged and Mobile blog.