instead of Firefox. To enable the repository and install Chromium:
Open Synaptic (System -> Admin -> Synaptic Package Manager). From the menu bar, from the Edit menu, select "Repositories". Software Sources will launch. Click the "Other software" tab, and then click the "Add" button in the lower left corner of the window.
In the dialog box that pops up, type in ppa:chromium-daily/ppa
in the box and two new repositories will be loaded in there. Click Close, then Reload. After the software listings are updated, search for "chromium-browser" in the search box in the upper right of the Synaptic window. Mark the one package that shows up for installation, and then click "Apply". The package will then install automatically.
Now, to run Chromium, just select "Chromium Web Browser" from the Applications -> Internet menu.
If you're still having choppy video in Chromium, make sure you have true Adobe Flash, **NOT** Swfdec or Gnash (the other two plugins in Firefox's Plugin Finder) installed. Remove Swfdec and Gnash in Synaptic.