Do you want to tell him at all before you are 12 weeks?

I had to tell my bosses at work because of the nature of the job I did, so they knew at 6 weeks.
I just came out and told them. I hadnt been there very long either, and was very nervous as it was a long term position. I actually made a comment at the interview that it "wasnt like I was about to run off and have kids anytime soon" - I was already pregnant and didnt know lol

Anyway, the best way to tell them is just to take them aside when you have time, put everything out there and say this si the situation, this is what I would like to happen, and ask if they have any comments or special requirements in this situation (extra health precautions, or issues with you being pregnant)

Good luck hun!