Very easy to replace. the bottom end unscrews from the VSS housing. The top end just pulls out. The only trick on removing the cable is to make sure to grab hold of the connector, not the cable, or you could break it. Snaps back in, just a simple push.
But I can't stress it enough. Once you get the speedo case opened, do NOT touch the needle. I'm not kidding when I say it's as fragile as a watch spring, since that's exactly what it's connected to. And when you get it out of the housing, don't touch the little twisted tabs on the back of the guts.
My fix really is a last-ditch try to save the speedo, there is a lot that can go wrong in it, so no guarantees that it will fix your problem. Take your time, be careful, and only touch what you have to. Also, be careful taking it out of the dash, the light bulbs are easy to break off too.
My oil line fix
My 100k stopped odometer fix
Brace for impact, I'm in a "modifying mood". Massive thread count inbound.