As a follow on from the Mac OSX updating info posted above, this post from CNET notes the following:

"Some people may still wish to use older versions of Flash player for compatibility reasons. Even though new versions of the software will contain fixes to vulnerabilities, sometimes bugs may appear that result in broken functionality or poor performance, and having this auto-disable feature will force the use of faulty updates".   

If this happens to you, the good news is that "Apple's browser does not prevent the use of older versions of Flash, and merely disables them when newer versions are available". If this applies to you, the details of how to restore use of an older version of Flash are provided at this link.

http://reviews.cnet.com/8301-13727_7-57432867-263/how-to-re-enable-older-flash-i

Cheers,

Andrez