Google Chrome for Linux does not officially exist yet, not as "Chrome" but as a pre-alpha project called "Chromium". It's a really early build so don't go filing bug reports for it. And definitely, it won't replace your firefox or Epiphany. Atleast not that soon. So let's get started. Let me remind you one last time, Try at your own risk :)
1. Edit your apt source list.
and append the following lines at the end
deb http://ppa.launchpad.net/chromium-daily/ppa/ubuntu intrepid main
deb-src http://ppa.launchpad.net/chromium-daily/ppa/ubuntu intrepid main
2. Update your sources and install Chromium
$ sudo apt-get install chromium-browser
3. Time to test drive