In short, the proposed law would prohibit employment discrimination based on sexual orientation and gender identity. The gender identity provision may cause a stir as it was not in the last failed version of ENDA. Oh, who am I kidding, the sexual orientation provision will cause a stir too.
Of course, ENDA would also prohibit retaliation. There would be exceptions for any organization exempted from the religious discrimination provisions of Title VII. Military would also be exempted. Browsing through the bill (the number is HR 2981 by the way) it looks like there are about bajillion references to Title VII. That's not an exact count. It looks like the bill seeks to more or less throw sexual orientation and gender identity on to the Title VII pile.
For more information, The Employment Law Post has a nice little article on ENDA. I don't think we've heard the last of this one by a long shot.