One of the good feature in gmail chat that you may miss will be SMS chat. Frankly speaking I had read an article sometime back in google blog but I have noticed the feature yesterday only. The feature can be enabled from google Lab tab in settings window of gmail. This feature is currently live in US only. After enabling it in the Lab tab follow the steps below.

1. Enter your contact’s name in the ‘Search or invite friends’ box in Chat, and select Send SMS from the box of options that appears to the right of your contact’s name. Or, if you already have a Chat window open for this contact, just click Video & more, and select Send SMS.
2. In the dialog box, enter a phone number in the ‘Send SMS messages to this number’ field. For now, this feature works only on United States phone numbers. If you’re outside the US, you can still use it, but you won’t see the SMS option in Chat until you enable it manually in the Chat settings page.
3. Click Save.
4. A Chat window appears. Just type your message as you would normally. When you hit Enter, the message will be sent to the phone number you entered.

If the recipient respond to that chat message it will be displayed like normal chat. Moreover it will be logged in chat history but the offrecord will not work with this as it is using SMS as the mechanism for chatting.

Another important feature is that every user will get a virtual phone number for sending the reply back.