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!

i'm also looking for this same answer...anybody?

I'm sure there is something either in here in the sponsors or on the Crackberry website
the first one is a link from the sponsors section here

Blackberry Headsets - OEM BlackBerry Dual Buds Stereo Hands-free Headset 3.5mm, White


Seidio Audio Adaptor w/built-in mic and answer button - ShopCrackBerry

I have the Shure adapter which works great and the mic quality is excellent.
Shure * - Music Phone Adapter

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).