The Knitting Fools web site has a sweater pattern generator
that may be of use to you.
As I have said I have not knit any sweaters but as I understand it. Knitting a sweater from the bottom up, when you reach the point the "V" neck is to start, 1/2 of the stitches will be moved to a stitch holder (waste yarn, spare needle, official stitch holder). The live stitches will then be knit, every other row will be reduced by number of stitches necessary to create the width of "V" necessary. Once you have reached the shoulder seam bind the first side off.
Pick up the stitches off the stitch holder and knit the second side as the first side was knit.
I have now exhausted my understanding of sweater knitting.