The last firm thing we’d heard about this was that f2p was apparently off the table for Vanguard; it was such a tiny game that the required investment was seen as not worth the trouble. Now SOE, with big successes in converting DC Universe Online and EverQuest II (and recently EverQuest,) have changed their tune. Most likely, this is the end of the line for SOE games on the old subscription-only model.
Details are thin on the ground at this time, but what we know so far is that there will be a larger development team, more frequent updates. I would expect we’ll see something not dissimilar to SOE’s other f2p models, although they do have more room to experiment in this case; it’s not as though they can drive the player numbers down.
For me, and I realize I’m stating a minority interest here, this is the biggest possible news to hit in months, amid all the press for high-profile games like SWTOR and GW2. It is, for me, the final death knell for subscriptions.