Take two butter knives, slip them between the needle and face, and
twist them slowly and evenly.  Should pop right off.  If the parts
speedo is in good shape you may want to slip a rag in there to keep
from scratching the face.

As an aside, if your gauges have orangey-red needles, Plasti-Kote makes
a hobby paint that is a damn near perfect match.  I think it's called
"orange glow" or similar.  I use the brush on as it's semi-flat and
flows out nicely, actually does a better job than the spray.

nate