Here is a little program I wrote for viewing vectors in three dimensions:
http://www.bodurov.com/VectorVisualizer/
It also includes a small 3D engine for drawing and rotating a group of lines in 3D. Full source code is available at: http://www.codeplex.com/VectorVisualizer
You can also download offline version from here: http://www.bodurov.com/files/VectorVisualizer_Offline.zip