Best drawing tool I use for flow charts, state diagrams, etc is called Visio. Once you use it you will see why.

Before you say,,,,I cannot afford to buy it...please consider the value of your time to use what is probably the best tool for this job. A good tool can save you many hours of time over a crappy tool.

Also note that is is not necessary to have the latest version of Visio in order to make effective use of the program. I would check out eBay to get a version such as Visio 5 for example. Here is a link to a typical auction for a copy. Not that expensive !!

Michael Karas