When stripes are knit in the round, the beginnings and endings are uneven. There is a simple way to get nice, jogless stripes:

-         start a new color round, change yarn and knit the first round like usual.

-         Next round, slip the first stitch.

-         Knit on like usual untill next color change.

If you knit a lot of small stripes you may want to knit travelling stripes. Let the beginning of each stripe travel one stitch to the left, each time you change colors. This way every part of every row has the same amount of rounds. Learn more about this at Techknitting's blog

http://techknitting.blogspot.nl/2011/03/jogless-stripes-pretty-picture-version.html