We asked for this a while ago, and MN said that they'd work on it, but since then they've included a question about who would use it in their census, so I guess they are still judging the need.
It's an app for all mobile phones that is needed, not just i-phones.
It needs to make the pages smaller to load - a single screen is in excess of 1.6mb, which makes it deathly slow. Cut out the logos (fills the whole flippin screen!), remove all the extra boxes on the talk pages (eg the mumsnet latest one, which sometimes appears in the middle of the threads I'm on, or after the thread title but before the posts in a particular thread (v odd why it's sometimes there and sometimes on the right) as a bare minimum, and pref simplify the ads (obv I'd like them removed, but appreciate that as a business they prob need to stay).