Ok, thanks, I found a picture of it on ravelry - http://www.ravelry.com/patterns/library/preppie-in-pink-and-blue
For the sleeve, the increase sts are at the edges, so you will be adding on at the outside of the pattern st.
So say your pattern is - vvvvpppppvvvvpppppvvvv - you add in new sts (n) - v[COLOR=Black][B]n[/B]vvvpppppvvvvpppppvvvn[/COLOR]v and the next row would be vvvvvpppppvvvvpppppvvvvv, than after another inc you would have - vpvvvvpppppvvvvpppppvvvvpv
And after another inc it would be vppvvvvpppppvvvvpppppvvvvppv and keep add in the new sts to the pattern, while keeping the edge st always a knit on each RS row.
This may not quite be what your pattern really is, I'm just showing you how the middle sts of the pattern would stay the same, but the new sts get added however they would be knit if you had more sts to begin with. If you mess up a little, it may not show since they would be close to the seam.