They claim that there will be an OGL version of the rules, but details are extremely vague (frankly, I remain skeptical at this time).
And as of today, that's turned out to be the case. There won't be on OGL for 4E; instead there will be a brand-new license called the "Gaming System License" that is a far more restricted grant of rights than 3E allowed (Feb-2, http://www.enworld.org/showthread.php?t=218031 ):
Mike: Why is Wizards of the Coast calling it the OGL when it really doesn't seem quite open?
Linae Foster: We decided that yeah, OGL isn't the best name for it. So we're going to call it The Game System License from now on or GSL.
You can see comments and links to the prior "OGL" post here about why that was probably necessary. In particular, it's been pointed out that OGL v.1 Section 9 actually makes forward-referencing grants of rights to anything ever released under any OGL. (i.e., WOTC wants OGL v.2 with lots more restrictions, but OGL v.1 says you can take any such content and just re-release it under the less restrictive OGL v.1 anyway.)
So, as of today no more use of OGL by WOTC. I actually think that's positive, in that they're being up front about it and not trying to confuse/FUD-up the legal standing of the first OGL.