I got my Jawbone II a few weeks ago and it was working really well until a few days ago. Over the last few days, I've been getting really bad static, despite being really close to the headset (I usually keep it on my belt, but it even happens if I carry my Curve in my shirt pocket).
I agree, exchange it. As SNA2760 has stated, if that is the case with the Jawbone II then simply exchange for a different brand/model. Sometimes that is the only way you will ever find the perfect one for you.