If you want to draw graph with a PIC, almost GLCD (graphic LCD) would do the job. There's some PicBasic code example for some GLCD controller at the following link
http://www.compsys1.com/workbench/

i'd never use any part of their code but we already heard some good comments here. They also provide some software to create your own screen.

Now if you want to send your data to a PC and plot your graph... EXCEL could work, or any other programming language you're comfortable with (Visual c++, Visual Basic,... Assembler... )