Last year I finally went with HobbyWare's Pattern Maker Professional and I've been very pleased with it, but you might prefer something else.
For my fourth edition, I'm using one of the software packages expressly designed for needlework patterns and I've been looking at every major cross-stitch program I've been able to find on the net. The third edition was created using Microsoft Paint with black & white BMP files: I drew 'graph paper' and then filled in squares using the program's selection of shadings. The first and second editions of my Designs, Period book were published from patterns hand-drawn on graph paper. DragonBear: Links to Cross-Stitch Software