I have an iPhone 3G in the Vancouver area with the $10 "data plan". Most apps work fine with the 3G service. However, no IM client will connect unless I am connected to WiFi, whether it's Gtalk (safari based), Windows Messenger, Fring, IM+, or Ebuddy. I even purchased "3G unlocker", a Cydia (jailbreak store) app that fools apps into thinking they are getting data from a WiFi source instead of the 3G source they are using, but with no luck.

At this point, my theory is as follows: instant messaging is constantly pulling and pushing data from the network little bits at a time. The Speakout network recognizes this and quickly puts a stop to it, for whatever reason.

Is this a valid theory? Has anyone successfully got an IM client to work? I'd love to be able to chat while I am riding the bus.

Cool. Thanks for the reply. Does all instant messaging use these unsupported ports? Can these programs be fooled/configured to use port 80?

I am also trying to get whatsapp to work, but there is no web based version. I don't think I will have much luck there.

I can't stand the eBuddy web based messenger. So I searched for a better one and found Mundu. iphone.mundu.com. It works perfectly on 3G. Messages are instant up and down, as opposed to eBuddy that only auto-refreshes every 10 seconds. The "data transfer symbol" on the top of the screen is constantly there when logged in, just like when you are logged into Gtalk or other apps on WiFi. The interface is excellent and works seamlessly. I encourage everyone to try it for themselves.

Yahoo messenger works.

Tried ebuddy. Seems to work fine when I actually have the app open, but when I close it I no longer get any notification of new messages. Yahoo Messenger is the only app that I've found thus far that will give a notification when the app itself is backgrounded.