Microsoft releases Internet Explorer 10 Update Blocker kit
If you don't want IE10 installed automatically, now would be a good time to deploy Auto Update Blocker
If your organization controls Microsoft's patches using WSUS or SCCM, the monkey's already on IT's back to approve the IE10 update when it appears: no need to run the IE10 Blocker Toolkit (unless you have WSUS Update Rollups set for automatic installation, which is definitely not recommended).
Fair warning: Microsoft advises that IE10 will be pushed through Automatic Update and WSUS shortly after it hits RTM -- in other words, in the near future. "Distribution of Internet Explorer 10 by Automatic Updates will begin slowly and take several months to complete. Customers can expect to be offered the upgrade to Internet Explorer 10 at any time in the months following the release of Internet Explorer 10."
As best as I can tell, the IE10 Auto Update blocker works much the same as the IE9 Update blocker. Like the IE9 Automatic Update rollout, I expect IE10's rollout to start as a very slow trickle, with plenty of drama, angst, and bad information in the limelight.
The IE10 update, once started, will proceed without any notification. Microsoft says, "The automatic delivery process will notify users that an update is available and allow users to choose whether to install Internet Explorer 10. Automatic Updates will only offer Internet Explorer 10 to users with local administrator accounts. Automatic Updates will automatically download and install Internet Explorer 10 when it is available for Automatic Updates delivery. There will be no notification or prompt to indicate the installation process."
If you or any of your users are running the IE10 Release Preview (which only runs on Windows 7), they'll get upgraded to the final version of IE10 shortly after it appears, whether the IE10 Auto Update blocker has been run or not.
Running the IE10 Blocker Toolkit permanently prevents IE10 from being offered as an Automatic Update. It does not prevent your users from downloading and installing IE10 manually. There's an "unblock" routine included in the toolkit package.