In 3.5 being 2 handed has nothing to do with the feat (weapon sizes and off hand weapons function a lot differently in 3.5).
Complete Warrior (3.5 version of the feat)
Allows you to wield a "larger" weapon as if it were appropriately sized but you still suffer the incorrect size penalty (i.e a -2 on attacks) and you can[t use it for your off hand.
There is an epic feat "Wield Oversized Weapon" pg 154 of Complete Warrior that would allow you to wield a larger wepon in your off hand as well.
Sword and Fist (3.0 version) says you can use 1 weapon that is 1 size larger than you in one hand and then you suffer a -2 penalty on attacks.
I would say that since it states "1 weapon and 1 hand" then it is stongly implied that you can't apply this to the off hand.
Additional information: Don't take Monkey Grip. It's a trap unless you're a really, really large character. And no, it doesn't stack with Powerful Build.
There should be a feat in "Complete Adventurer" or "Complete Warrior" that is called "Oversized Two Weapon Fighting". Should have some TWF prerequisites and maybe STR 13 or so. It allows wielding a medium sized weapon in your off-hand without the usual penalty.