wpa2 personal uses preshared passphrases to connect various devices to the wireless network; this is probably what 99 % of all home users use. the wireless device takes your preshared key and hashes it
with your ssid name and sends the information via a 4 way handshake to get the current encryption keys and these keys change at regular intervals (default 1 hour)
im not 100 % sure on this one. but this is the impression i get.
wpa2 enterprise relies on an authentication server, and i believe each cient is given a different encryption cipher or the server is the one that has the keys and gives the current keys to the client. the cient does not use a preshared key. the only time i ever used wpa2 enterprise was google secure wifi in mountain view