Worm composters (worm bins) are available on eBay from $20, to this $90 model (pictured on right) to even $130. There used to be a listing for a cedar worm bin that I really liked (and only $79 plus s & h!, but I don't see them anymore. See below for links to build your own bins.
Tonight I am bringing my worm bin. I will donate handfuls of worms to those of you who bring your own container and who promise to care for them. Two links, below, have lots of very good worm composting/vermiculture data you might enjoy.
Earth 911 has a good article that includes a video.
And Vermiculture Northwest is chock full of composting and worm bin information. One bin, from Washingtion State University, called a cheap and easy worm bin, includes complete instructions on building it.