why does my spedo move

89 s-10 2.5 5 spd man trans..... Does anybody know why my spedo moves to 10 mph when I hit the gas while in neutral and not moving?

your speedo goes into the transmission, and even though your in neutral some of the gears can still move a bit. It might be all that your speedo needs to move

does this mean that something is wrong, or more like just old and worn?

I wouldn't worry about it. I've seen lots of cars do the same thing so I would think that t's fine

thanks