http://knittinghelp.com/knitting/vid...ess-stitch.mpg
This is my favorite joining technique. Works great for sweaters.
For blocks of an afghan, though, it might be better to join them end to end--picking up part of a stitch from each edge back and forth. This way they meet flat, if you know what I mean.
Found a picture!
http://www.knitting.co.nz/site/page_...learntoknit13/