Oh, good question, SubLGT! I'll definitely have to keep my eye on this thread.
I do a couple of things, though they require a little work. I occasionally go to UMTRI's online library and see if they've got any interesting articles available. It's more technical reading than anything else, but that can be a good thing.
SAE International (sae.org) can have some cool things for free on their website, you just need to meander and look through a little. There are also some textbooks on there I've got my eye on for when I have the money (not all automotive lighting related). If that kind of reading is your thing, Virgil recommended Automotive Lighting and Human Vision to me a while back, it is probably going to end up as a late Christmas present to myself with some money I received.
Then you've got automotive publications that you can search through for the occasional lighting news, especially if you're going to be there anyway. I like Automotive News and Automotive Engineer.
Lastly, you might check automotive enthusiast publications such as C&D, Motortrend, Autoweek, and Automobilwoche. Just watch for when they just regurgitate what a company's marketing team told them.