Last month Adobe announced they were stopping development of Flash for mobile platforms. Then when the Galaxy Nexus was released in the UK it was found that the version of Flash in the Android Market was incompatible with Ice Cream Sandwich. Google and Adobe both advised that this would be remedied with Adobe going as far as promising this would be done by the end of December. Well this has now occured and you can download it to your new Galaxy Nexus from the Android Market, coincidentally just in time for the Galaxy Nexus release in Australia and also the release of the LTE variant of the Galaxy Nexus in the US.
The release notes for Adobe Flash 11.1 from the market :

This update to Adobe Flash Player 11 includes compatibility with Android 4 supported devices, performance improvements and bug fixes related to security and stability. The complete set of release notes can be found at:

I thought I was done with Flash on mobile, however the last 2 weeks with my Galaxy Nexus has shown me there are still a number of sites out there which I frequent regularly that utilise the Flash plugin, i`ve become very familiar with a little blue block representing ‘plug-in missing’ on a number of websites and the availability of Flash on Android 4.0 is extremely welcome. I can only hope that by the time Android 5.0/Jellybean rolls around sometime next year that the web has sorted this out and moved over to HTML5.

Source: Android Market.