ddrobins.1956.......here's a website that has very clear instructions on how to make the afghan stitch. The afghan hook is like a cross between a knitting needle (has a button on one end to keep the thread from coming off) and a crochet hook on the other end. I guess the standard length is 14 inches long and they come in different sizes like crochet hooks. I can't find them at Walmart anymore, but there are several listed on eBay, Amazon, etc. and you can probably find them in regular sewing and craft shops.
You'll see once you've crocheted a piece how well it lends itself to cross stitch.
http://vickisdesigns.tripod.com/basics.com
Hope this helps.