DH will definitely be first to know. My boss will actually be second, most likely, just because he is my BFF, and also because I work in Infectious Disease, so it determines what patients I see from then on (a lot of stuff I have to avoid).
My parents and sister, as well as DH's family, I don't think we'll tell until at least 10-12 weeks. First of all, because my mom will give us crap for getting pregnant before I lose weight, while DH is out of work, blah blah blah. Plus, I really want to make sure it's a sticky bean. Dad will be supportive, my sister could go either way - she can be a little difficult. DH has three brothers, one of which we don't speak to. The other two will be thrilled - they love kids. Friends - closest will know first, and then I'll just let the word get out whenever it does...
I dunno, it's complicated. I have a feeling DH is going to be the one to spill the beans early, though.