Just got an email from the IT boss at work. Not having an iPhone it doesn't mean anything to me, and I don't know how relevant it is in the 'real world', but the fact that one of the 'ordinary' IT staff managed it presumably means it could be significant:
For anyone who thinks their iPhone is secure, please read the following
The result is that even if you have a passcode, your data is still freely available if you (or someone else) plugs your phone into a PC with a recent Linux release, eg Fedora 13, without any sort of authentication.
[One of the IT staff] has tried it and can confirm this.