As of 2011-04-15, the version of uzbl available on Ubuntu is a year out of date. You are probably best off installing from source:
1. Install git and uzbl dependencies:
Uzbl has other build dependencies, but installing libwebkit-dev should bring them all in.
sudo apt-get install git git-core libwebkit-dev
2. Fetch uzbl from git:
git clone git://github.com/Dieterbe/uzbl.git
3. Install uzbl:
cd uzbl make sudo make install
4. Install dependencies of the example scripts:
sudo apt-get install socat dwm-tools zenity xclip python-gtk2-dev
5. Start using uzbl!
uzbl-tabbed
or
uzbl-browser