On March 10th, 2009 innerfence (maker of Infinite SMS) was told that the next day the SMS feature of Google Chat would be closed to 3rd parties, therefore shutting down Infinite SMS.
For many, this feature was the saving grace from the greed of cell phone companies. Google chose to shut it down because it got "too popular" and "cost too much money to maintain." Honestly, I am sure there are much better solutions. Here's to getting what we had back.