I've found that a lot of things on Ubuntu are very easy to install but there are some trickery ones that if you don't know the procedure can be a pain to get up and running on a new installation. Here is a quick setup guide for getting SmartGit installed on a fresh Ubuntu installation.

1. Install the Java Runtime Environment from here. http://apt.ubuntu.com/p/openjdk-7-jre
2. Install Git with the command sudo apt-get install git-core
3. Install Mercurial with the command sudo apt-get install mercurial meld
4. Download and install SmartGit per their instructions on their site

That's all there is to it. Hope this helps both myself and anyone else looking for a quick guide to get SmartGit up and running.