It actually isn't spooky at all once you understand it properly (but it is almost never explained properly, especially in the popular press). Measurement and entanglement are really the same phenomenon. The process of "measuring" photon A was actually begun when it became entangled with photon B (and vice versa). We call it a "measurement" when a large number of particles (like a measurement apparatus or a brain) become mutually entangled with each other. See:
lisper, actually measurement is the act of collapsing the wave, and entanglement only exists before the wave function collapse. It's possible to never measure something, and it could be entangled forever.
You didn't read waqf's comment, did you? You may have read my comment but you clearly didn't read my link.
> actually measurement is the act of collapsing the wave, and entanglement only exists before the wave function collapse. It's possible to never measure something, and it could be entangled forever.
Entangled particles continue to be entangled even after they are "measured". If this were not true, faster-than-light communication would be possible. To understand why, read the paper.
The only way to "undo" an entanglement is to time-reverse the process that created the entangled pair to begin with, i.e. to bring the members of the entangled pair back together.
http://www.flownet.com/ron/QM.pdf
for a more detailed explanation.