If you're looking for php based software to do charts and graphs, check this out.
I started my project with jpgraph but it was really lacking a lot of features. Yes, it's completely free so I can't complain. ChartDirector is $99 for one license but it's excellent. It's far more flexible than jpgraph. One of the things I like about it is that I can put custom text boxes anywhere on the graph. It's got it's own markup language so that I can mix colors, fonts, etc. all in the same text string.
I highly recommend you check out the demo versions of both before making a decision. Jpgraph just might be enough if you need simple graphs but it lacks a lot.
JPGraph & ChartDirector
Moderator: General Moderators
Re: JPGraph & ChartDirector
you might also want to look into FusionCharts.
Re: JPGraph & ChartDirector
I did but I'm outputting the graphs on a PDF so I didn't need the flash aspects of it and the price is considerably more. It might work for other projects in the future though.