While I can't speak for Sophos, I don't expect any Antivirus solution for the iPhone in the foreseeable future. I attended an Apple presentation concerning the use of iPhones for corporate use, and the question arose, naturally.
The Apple representative saw no demand for AV on the devices, and stated that the current APIs for developers do not allow any process to scan anything but their own data, which is quite pointless.
For Sophos or any AV-vendor to support the iPhone, would require first Apple to change their mind, secondly, the creation of APIs which allow third-party-software to scan the whole device.
