Very similar, yes. It's a bit different in that with spins, each measurement only has two possible outcomes, whereas a position or momentum measurement can yield a range of numbers, but in both cases the idea is the same. A very precise position measurement means that you've generated a large uncertainty in momentum.[*] Measuring the x component of a pin means that you no longer know its z value, even if you previously measured it. The more mathematically-dense but precise statement is that a a projection along S_x ("an eigenstate of the S_x operator") is a superposition of the two S_z states, so by performing that measurement and getting let's say +1/2, fhat puts the system into a Sz state of 1/sqrt(2)( |+> + |->), which is to say a 50% chance of spin up and a 50% chance of spin down. [**]
[*} Favorite SF weapon: The Heisenberg Disrupter. It measures the position of all of the atoms in its target very very precisely, at which point the target explodes away from itself at nearly the speed of light....
[**] For those who haven't seen this sort of notation before, it's called Dirac or informally bra-ket notation and it's for talking about quantum states and the various ways of evolving or measuring them. In this case, it means a state consisting of an equal probability of spin-up and spin-down; the 1/sqrt(2) prefactor is so that when we add up the total probability of all states, we get 1. If I had measured along S_y instead of S_x, it would have been |+> - i |->; the relative weights of the two states are complex, and encode things like phase shifts.
