Google rolled out iGoogle chat in English for U.S. users, and will soon release to other iGoogle supported languages and countries. Similar to Gmail chat, people will be able to send instant messages from their iGoogle page. If you're already a Gmail chat user, all your current chat settings will apply to iGoogle. You will also be able to chat with friends who don't yet have a Gmail address, just invite them as a chat buddy, and if they accept your invitation and sign up for iGoogle with their personal email account, their name becomes just a click away right on your page. You have a couple of options to hid the chat feature. You can either click the chat “options” link and selecting “hide chat,” or sign off completely by selecting "sign out of chat."
If you don't see it on your iGoogle page and you simply can't wait to check it out, feel free to opt in by going to www.google.com/ig/v2invite.