FWIW I have had to reset my password about 4 times in the same amount of months including today... It does get frustrating to say the least...
Probably due to your iPad/iPhone trying to log in over and over with an incorrect password. That's what did it for me, no hacking, no password phishing, just my iPad locking me out of my account.
Bloody stupid policy. I'm happy with my WP7 phone though. I have money set aside for a new phone still. Every time i think of getting a 4S i remember this and i put my credit card away.
EDIT: i can't believe i was voted down on my earlier posts because of bad customer service i received.