Thanks for this great guide, I've used some its tips to rewrite the copy in the mobile site for the Bay of Islands. It would be interesting to have an update specifically for iphones, I've noticed even less copy on those iphone-specific sites.
Some other interesting things for mobile copy I've noticed - if you have a login page, don't bother with the 'lost password' link, and once logged in, leave the 'log out' right at the bottom - the phone is so personal that there is not going to be a need to log out.