TMo has been available at LGA for a few months now -- a welcomed change! ^ ^
The last time I was at the LAX RCC Boingo was still available; this was about a month ago. I had to sit to the far right (as you enter the club) towards the work carrels to get a halfway decent signal.
According to the Boingo website, (boingo.com, go figure), it is still up and running at 6,848 locations around the country and at least that many more around the world. This includes Terminals 1-7 and TBI.
Not sure what the story is, but will be there in 2 weeks -- I am sure other FTers can report back before then!