I'm not a great fan of Heidegger, but if you have to read him what better way than to have Hubert Dreyfus take you through Being and Time. Life is short. If you are going to approach this monumentally obscure book at all you need a guide. Everyone does. Or else, perhaps, it would be wiser to avoid the book altogether. I believe F.R.Leavis' line on certain books was 'The critic has his economies' - i.e. critics don't need to read everything. But if you feel that you really should grasp Heidegger's main themes...then you definitely will need some help.
If you are at Berkeley, then no problem. But now we can all sit in on Dreyfus' lectures as all 22 (so far) of his Fall lecture series are available on iTunes - in the iTunesU. If you have the iTunes software on your computer, this link should take you to the podcast lectures. Also Dreyfus has links that should get you to them here. If that doesn't work, go to iTunes, then to iTunesU, then to UC Berkeley, then Arts and Humanities...Each lecture is about one and a quarter hours and is unedited - so it really does feel like sitting in on a course. Dreyfus is clearly a popular teacher - the lecture room is full to bursting.