I created this applet because I couldn't find one that would allow me to actually REVOLVE the function around the axis. There are lots of applets that will generate the resulting solid, but this one also allows you to revolve the function through any angle you choose. This should aid students in being able to visualize how these solids are created from the original function.
You can also input any function you want to work with, as well as change the upper and lower bounds of the "integration".