Looking for help with headphones

Sorry if this is the wrong forum- I think my question could probably go in a few different ones. Here's my setup. I've got an 42LG50 flatscreen that is hooked up to a Sony HT-SS2300 HTIB. I've got a 360 hooked into the HTIB. All sound is currently handled through the HTIB as well.

I'm trying to find a way to hook up a regular pair of headphones with a 3.5MM jack.

I guess it would be acceptable to know how to plug into the Xbox, since that's what I'd be using the headphones for 95% of the time anyways, but it just seems like it would be better to have the ability to listen to anything that is passed through the receiver if I wanted.

Any suggestions? If plugging into the receiver isn't possible or too expensive, can I do it straight to Xbox somehow? I don't care about live chat or anything- I just want to be able to listen to games I'm playing.

Thanks so much in advance, and sorry for the noob question.