I sat down with Barbara Walker’s Treasury (BWT) book 3 last night, and it started the wheels turning. This is the book about charting.
Of course I immediately wanted a digital way to convert text instructions to charts. I found several, though my search was much more successful after thinking to look on Ravelry for a group talking about charting patterns. The Symbolcraft group had a thread on knit charting software that lead me to these intriguing sites.
Jacquie has a great visual chart designer at http://jacquie.typepad.com/Charts/knitChart.htm
To convert text to a pdf with symbols, good-natured ribbing has presented CHART-A-RAMA
And the do-it-all tool that is not free, but worth noting is Knit Visualizer by Knit Foundry. This was recently mentioned by the Yarn Harlot (Nov. 6, 2007), and based on the Demo version I have been playing with, it seems pretty powerful. She is going to be releasing a new version very shortly, so that should be neat to see.