Check out Amy's videos on Picking Up Stitches. It will show you how to get 'live' stitches on your needle to knit on the border. You'll need a long circular needle to fit all the stitches down the edge of a scarf, though.
Once you have the stitches on there, you can knit any kind of border that you like.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry