I have purchased the extra ear tips for a Plantronics Discovery 925/975 and they fit perfectly on the Jawbone. And they are comfortable and i do not need the ear hook anymore.
www.plantronics.com/north_america/en_US/products/m...
Discussion about
Better Ear Tip and without the hook
I'm using the THE NEW JAWBONE NEW FIT EARBUD with my Jawbone 2 (which it looks like they are also calling the New Jawbone). They sent me this for free + $3 shipping a while back in March '09. It looks like now they are selling a 3-pack for $10. Definitely a better solution than anything I used before. It took them I while to get the earbuds right, but it works great ... no ear hook needed.

