In short, YES.
You can connect your zune on mulitple computers. However, when your connect a zune to another computer, remember to set it as a GUEST at the first window that comes up, or else your zune will sync with your that computer. You can now use your laptop to add media to the zune and charge it at the same time. Remember not to SYNC your zune, or else you risk losing your media on your zune that you sync from your desktop, not on the laptop.
Message me to tell me if my advice works. Or incite anger at me if i deleted your entire collection. Good luck.