I heard that too, and I also heard that Charisma Carpenter and Sarah Michelle Geller (both from Buffy) were apparently fighting for the part...
Well I for one hope neither gets it and Joss DOESN'T direct Wonder Woman, because it's set to be a PHENOMENAL flop! Unlike Marvel properties, the DC characters are gonna be a lot harder to make cool and, well, accessible because they are all so overly cheezy, overpowered and unadaptable (at least given current audience attitudes)...
That's why I believe that Superman will not fair too well, it wont "flop" but look at the original movies, they were crap! People will go watch it, as they will Batman, more because of the impression we have they were really good, but look back at the last batman and superman films and not only did they flop but they were utterly horrendous films. A character like Superman is just so... 2 dimensional when compared to Marvel's main man Spidey. It's simply an inherent flaw with DC characters.
Anyway, erm, yeah, go X3!!!
Pesonally I'm hoping Fox go all out and do what Singer originally wanted to do, shoot 3 and 4 together a bit like Matrix Returns and Revolitions, but not that crap. The first could see Jeans reappearance and slow transofrmation into Phoenix, whilst the X Men deal with the Sentinels, and the second could be Hellfire club and ultimately Dark Phoenix...
I'm such a geek...