OR YOU CAN JUST READ BELOW...
1) First turn your computer or laptop & launch ur normal web browser. If you don't have Firefox as your browser, download the newest version by following the instructions at http://www.mozilla.com/en-US/firefox/ie.html
2) Download the User Agent Switcher 0.7.2 at this web address
3) Once you have downloaded & installed the above links, open up ur browser. Go to the tools button on ur toolbar, switch from the DEFAULT USER to Iphone3.0 user. You may have to un-hide this option by clicking on Firefox Add-Ons and locating the User Agent Switcher itself, and un-checking the "Hide" box.
4) Then go to: Msnmobile.airg.ca
5) Sign into AirG like you normally would using your normal Screen name and password & CHAT AWAY!
Hope it works!