I've recently found this
http://kpg.sourceforge.net/
but I haven't tried it so can't say how well it works. The site that led me to it in the first place was this one:
http://domestikgoddess.com/3-easy-wa...tting-pattern/
Hope this helps!
ETA: Forgot to add there's another site I found for lace charting. Not sure if that would suit your purposes, and again I haven't used it myself yet, but the link is here:
http://jacquie.typepad.com/Charts/knitChart.htm