Using the current version of Chromium from Launchpad, adding Flash to the speedy browser is a breeze. H3g3m0n posted a tutorial on how to enable Flash in Chromium but that post is outdated and some more tweaking needs to be done for this to work:
To install under Ubuntu:
sudo su
echo "deb http://ppa.launchpad.net/chromium-daily/ppa/ubuntu jaunty main #chromium-browser" > /etc/apt/sources.list.d/chromium.list
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 0xfbef0d696de1c72ba5a835fe5a9bf3bb4e5e17b5
sudo apt-get update && sudo apt-get install chromium-browser
To enable Flash support:
sudo cp /usr/lib/flashplugin-installer/libflashplayer.so /usr/lib/chromium-browser/plugins
While it used to work with a symbolik link, it doesn't anymore, so you will have to copy the libflashplayer.so in the /usr/lib/chromium-browser/plugins folder when an update is available.
Then, you must run Chromium like this:
chromium-browser --enable-plugins
For extensions AND plugins: start browser with the following:
chromium-browser --enable-greasemonkey --enable-user-scripts --enable-extensions --enable-plugins