Neopets DreamTheme is a Chrome extension that lets you use any site theme you want on Neopets.
Close any Neopets tabs you have open.
Download the packaged extension by going here and clicking Download.
Open the Extensions page in Chrome (Menu > Tools > Extensions). (Or Menu > Settings > Extensions.)
Drag and drop neo-dt.crx onto that page, like so:
Wait for the following dialog to appear (sometimes it takes a few seconds). Then click Add.
Permissions explained (since Chrome makes them sound scary when they actually aren't!):
If all went well with the installation, you should see this message pop up.
You're all set! Open a new tab and go to Neopets. Or click here.
You should see an icon on the right side of the address bar, next to the bookmark icon. (If you don't see it, try refreshing the page.) It should look something like this:
The actual icon you see might be different because it reflects whichever theme you currently have selected.
Click on the icon to bring up the control panel. Then click on any theme to set it as your site theme! :)