Both of the domains associated with these ventures (http://gygaxmagazine.com and http://tsrgames.com) are little more at this point than a place to sign up with your name and email address to be sent the announcement when the first issue of Gygax Magazine is published in December 2012. Both are owned by the same person, apparently, who posted to the thread at ENWorld, and seems to be legit:
Hi guys, this is Jayson. I'm the editor for Gygax Magazine.
Gygax Magazine is myself, Ernie Gygax, Luke Gygax, Tim Kask, James Carpio, and Jim Wampler. Our first issue is out in December; since it's not finished yet, we've been pretty quiet about things until it's ready.
Just to address some of the questions, I thought it was best that I leave a reply. We do own the trademark for TSR, and have since December of 2011. We are a new company, not the old TSR, as they were purchased by Wizards in the '90s. The trademark was abandoned about nine years ago, and we registered it in 2011.
We decided the best thing to release first as TSR was a gaming magazine, because we wanted a way to bridge the traditions of the old guard with the awesome new games that are out today.I know that Tim Kask is involved with Eldritch Enterprises, similarly formed of a number of the Old Guard from TSR, but that doesn't seem to be connected with this. This TSR Games (note, not TSR Hobbies) is a completely new entity. Details about the magazine are sketchy as of right now, but hopefully more information will be forthcoming soon.
(h/t to Mortellan)
Please, if you haven't done so already, consider supporting my Kickstarter for the Adventures Dark and Deep Players Manual, going on now through December 19th. I need your help to make it a reality!