Does anyone make a voice headset system that allows you to plug in your own headphones? i.e. it would plug into the 1/8" jack on the 8310 and then has a mic module. The mic module would have another 1/8" jack for your own stereo headphones. Does anyone know if there's company out there that makes a product like this? Thanks!
Another vote for the Shure Music Phone adapter -- works great. I use it with my Sony MDR-71 headphones while commuting (nice thing about the Sony's is the headphones come with a very short cord, plus an extension cord; the Music Phone adapter replaces the extension cord so you don't have 6 feet of cable hanging off of you).
Available at the Apple store for $39.99 (as it works well with the iPhone).