ITT VIS will be holding a IDL User Group Meeting at AGU this year on Wednesday December 16 starting at 5:00 pm. And, of course, they will also be in the exhibit hall at booth 821.
Tech-X will also be in the exhibit hall with a couple IDL-related products: GPULib and the Remote Data Toolkit, my project to improve remote data access using DAP in IDL. I will be at the booth regularly, though not all the time, from Monday through Wednesday.
Full disclosure: I work for Tech-X Corporation and have worked on both GPULib and the Remote Data Toolkit.