POCKET ACES PROBABLITIES

[PHILIVEY1]

OK, I was playing in a tourney (not online) a couple weeks ago. I was heads up and got raised with pokcet aces. I reraised and the other player went all in, when he showed low and behold ha has pocket aces too. What are the odds of this happening heads up? Now the most bizzarre thing about this hand is that we are both figuring well just split the pot but 4 diamonds come on the community and he hits a flush. What are the odds of each pair of aces winning the pot?
I was also wondering what the odds of kk vs aa happening heads up and kk busting aa. This has also happened to me. THANKS!