You won’t be wowed by the sound but for something portable on a budget the PYT is an option
Compact, lightweight, cheap
Weak bass, harsh treble
This portable iPod speaker dock from Voix allows you to click your iPod in to place surrounded by a secure cocoon of speakers.
Powered by mains or batteries, it's compact, lightweight and compatible with the iPhone, Touch, Classic and nano (there's a line input for other portables). And you can turn it horizontal for movies.
There's little in the way of bass, and a harshness to the treble at loud volume. But hey, if you really want something compact, portable and battery-powered that adapts for videos, then this does a job