I've been working on test pieces for my beginning lace knitting class coming up in July at Fiber Christmas In July, and part of that will be how to do a knitted-on edging. While I was working on it I decided to take a few photographs (that's my leg/knee in the picture so obviously this wasn't really planned out). For your knitting pleasure, here's a basic tutorial.
This first picture shows the border at a 90º angle to the body of the work. (In this case, a scarf.) I tried to arrange it a little more nicely, but I had to have one hand for the camera. You can get the basic idea though—the body stitches are on the left needle with the edging stitches on the right needle. With the needles in this position, the return row of the edging has just been worked.
Tip: I usually like to end all of the stitches on the left needle since if I have to put the work down, sometimes it slips out of the edging stitches fairly easily.
In this picture I've arranged the work in a better working position, and you can see how the last edging stitch is going to be joined with the body stitch by knitting two together. I've got one picture without labels and the second with labels, and it got hard to see what was going on once I started labeling. [Click on the pictures to make them larger.]
In this next picture the body and edging stitches have been knitted together (although it's hard to see-be sure to click to enlarge!).
In this picture the edging stitches have been worked and you can see the join with the body and edging stitches. I like to have things oriented so that the right-hand needle holds the edging stitches and the edging/body joins are made at the end of a right-side (edging) row, but that isn't always convenient.
In this last picture you can see the completed border. One thing to note is that the joining stitches change part-way through--this is because I dropped down the joining stitches and worked them back up, but forgot to twist the slipped stitch as I worked them back up. (That might be a post for another day.) If you want to know more about that technique, it's from Joan Schrouder (who is amazingly awesome, not to mention incredibly nice!) in the Best of Knitters: Shawls and Scarves book, around page 68 or so.
So that's my little tutorial on knitted-on edgings. If you have any questions please let me know! Like I said earlier, this was a spur-of-the-moment thing so if something needs clarification I'll be happy add more.
I hope you're all having a great week!