anti-aliasing

how does one turn on anti-aliasing in blender

Maybe this:

The standard, built-in bump mapping and perspective-corrected mip-mapping, filtering, and anti-aliasing guarantee outstanding images (set DisplayButtons OSA to ON for this).

http://wiki.blender.org/index.php/Special:Search?search=anti-aliasing&go=Go

Or, click the OSA button under the Render button. we call it Over Sampling/Antialiasing. You have choices as to how much OSA to do: 5, 8, 11, or 16 pixels.