Implications of Jail breaking ipod/iphones

[Russell Fulton <r.fulton () AUCKLAND AC NZ>]

I have had several people ask me about this and I have tried  googling
around the area but most the stuff I have found consists of lists of
dos and don'ts with little or no background info.

The basic question is what are the security implications of jail
breaking your iphone?

Clearly this allows one to install applications that have not been
blessed by Apple (with the risks that that entails).  Are their less
obvious risks such as making it easier for browser bugs to be
exploited to do damage?

Like most things in security I suspect that there are cases where
phones should not be tampered with and others where the risk is
acceptable.

I would also appreciate any good references to the iPhone security
model.

Russell