Last year, our school was blessed to have access to and use of two netbook carts. These are great! They are mobile. Instead of going to a computer lab, the lab can come to you.
With that said, depending on what you are doing on the netbooks, they can be quite loud. Typing a persuasive piece. Not so loud. Using any of the multitude of educational game websites or interactive stories. Loud. A teacher last year suggested that we get headphones for the carts. So we did. This is slightly more complicated than it sounds, though. We got Labsonic Headphones in two different colors so that we could have one color (gold) on one cart and the other color (blue/teal) on the other cart (close to our school colors). The headphones were less bulky than those used in the lab for the sake of space, but not cloth and thus lice-resistant.
We had a plan to hook the headphones onto a bar attached to the cart with library bags, because the containers we used for some other class sets of devices would not fit underneath of the carts. But a bar would do the trick. First we looked at A Frame Bars. As it turned out, they were too tall, not to mention expensive! We thought we could weld a bar to the inside sides of the cart and asked about the feasability of this. Then re-thought that. The access panel would still need to drop down. So, we needed something in that area, but easily removable. I had a picture in my brain of what would work. It was questionable as to whether what was in my brain actually existed. After a trip to Lowe's, it was decided that it did not. But, there was a perfect alternative. A magnetic curtain rod could affix to the access panel and easily remove if needed. It was strong enough to hold on tight, and could extend to the appropriate length.
The bag hooks fit on the bar (they'll come off the thinner end even more easily, but they work!). And, voila! Headphones for all!