Click on 'Account and Billing' or other suitable category in the left-hand side (it may be slow to open), then on a sub-category: at the bottom of the page you will see a link for 'live chat' (when available).
If you are not in the USA, go to
http://www.apple.com/support/mobileme/ww and pick your country. Follow the above process: the link will usually be to email rather than Chat.
Click on 'Account and Billing' or other suitable category in the left-hand side (it may be slow to open), then on a sub-category: at the bottom of the page you will see a link for 'live chat' (when available).
If you are not in the USA, go to
http://www.apple.com/support/mobileme/ww and pick your country. Follow the above process: the link will usually be to email rather than Chat.