Jeepz.com now has an Iphone application that allows you to view threads, reply and create new posts, even send and receive personal messages, all using a service called Tapatalk.
You can read more at the
Tapatalk website, and purchase the app for $2.99 in the
app store (link launches iTunes)
**Update - there is now a free read only version here -
http://tapatalk.com/. Android is also supported.