iTunes 10.3 beta has been released.
link: https://www.apple.com/itunes/download/
Apple has a 10.3 beta listed for download on their iTunes page, but when you go to dl it, it turns out to just be 10.2.2.
It appears that the beta is not yet available to all.

This happened with the last release.. It was released to those on Apple devices ad then to others.