Installing Homebrew on Lion
As per this question I ran the following command:

sudo chown -R `whoami` /usr/local


And then re-ran the homebrew command:

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.github.com/gist/323731)"
==&gt; This script will install:
/usr/local/bin/brew
/usr/local/Library/Formula/...
/usr/local/Library/Homebrew/...

Press enter to continue
==&gt; /usr/bin/sudo /bin/chmod o+w /usr/local
==&gt; Downloading and Installing Homebrew...
==&gt; /usr/bin/sudo /bin/chmod o-w /usr/local
==&gt; Installation successful!
Now type: brew help


I hope this helps someone in future!