For really nice looking graphics, there are a few great packages that will work. One is R. R makes graphs and also includes a data modeling language and advanced statistical analysis tools. You can create Postscript with R. It is easy to translate this Postscript to PDF.

To use R within a perl program, you could try Statistics::R. I have not tried this module yet.

PGPLOT is probably the best package available for drawing graphs, but may be too difficult for you on NT. PGPLOT supports many output formats, both vector and bitmap.

To use PGPLOT within a perl program, use PGPLOT. This module has worked for me.