There was a discussion on echalk today regarding a school's migration to Apple Macs and how their maths teachers were resisting the change so they could still use FX Draw on their PC's so that they could create graphical functions for printing and class use.
I was immediatly interested why they would still use a paid for program when there were quite a few free and open source alternatives.
So here is the list I came up with that were free and cross platform.
Going from simple to complex....
the open source Mac / PC - Maths Trax from NASA
http://prime.jsc.nasa.gov/mathtrax/index.html
the open source cross platform geogebra (my favourite)
http://www.geogebra.org
or the open source cross platform C.A.R Metal
http://db-maths.nuxit.net/CaRMetal/index_en.html
or if you really want to freak them out - the free open source cross platform Maxima and Sage
http://maxima.sourceforge.net/
http://www.sagemath.org/
