Is there any such headphones available for the N800, that have a control inline - so you don't have to use the screen each time you want to change a song? Or at the very least, is there software that can take advantage of a proprietary inline control/headphone set?

Some work has been done with BT headsets; check on http://www.bitsmithy.net/, but note that (barring some modifications to bluez) only one button may be recognized. I'm sure a similar approach may be taken with single-button wired headsets (e.g. Nokia's one that came with). Maybe even the same daemon would work. But multi-button is not necessarily possible without real work.

I'm using a similar (though independently implemented) setup, using a BT headset, and I have single and double presses handled separately; if that suits your needs, I'm willing to share my code, but it's less likely to work with wired; you're probably better off modifying the bitsmithy code.

cool, I never would have considered this idea. Though I use my N800 to control my pseudo-media server system via VNC...so, why not something to control the NIT's??? Then again, the display is so teeeeny I am not sure what sort of control would be useful/meaningful.

Just cool...I am waiting for wifi video & audio to a set of wifi video goggles with a headset built-in...

kagu uses the headset button to toggle play/pause. there's functionality to skip to the next song with a double press (the two presses should not be too close, maemo limitation) but i'm not sure it's included in the release or not.