Matt Soell dropped into the HBO forum to address the recent not on the board comment from Chris DiCesar at Microsoft. In short, DiCesar was just trying to be as conservative as possible, and as a result, understated what's being done on Halo.

Matt reiterates:

I spent a lot of time pestering people about the status of Mac/PC Halo in the days leading up to E3, and while I knew I couldn't say anything substantial at the show, I also knew exactly where the project stood. PC Halo may seem an abstract concept for an indefinite future to the PR folks because we haven't given them anything to say about it yet, but it is very real to those of us personally involved in making it happen.

Work on PC Halo continues. When we're ready and able to say more, we will. That it didn't happen during E3 is a drag, but the lack of an E3 announcement doesn't MEAN anything except that we haven't gotten much faster in 11 years.

As for other questions-- regarding whether Mac/PC Halo will have mods, or whether any more information about Phoenix is available, Matt's answer as a simple, not yet.