You can use iTween.ValueTo to do this... it's a little verbose, though.
void startTheTween()
{
iTween.ValueTo(yourSprite.gameObject, iTween.Hash(
"time", 0.6f,
"from", new Color(0, 0, 0, 1),
"to", new Color(1, 1, 1, 1),
"onupdate", "setSpriteColor",
"onupdatetarget", this.gameObject,
));
}
void setSpriteColor(Color c)
{
yourSprite.color = c;
}