Try git

Make sure you have git installed and all the dependencies:
sudo apt-get install build-essential git-core cmake zlib1g-dev libncurses-dev

then download by running
git clone --recursive git://github.com/genome/somatic-sniper.git

then to compile and install
mkdir somatic-sniper/build
cd somatic-sniper/build
cmake ../
make deps
make -j
make test

you can also install this way if you are root if you run
sudo make install

instructions here: https://github.com/genome/somatic-sniper

Looks like somatic-sniper1.0.3 isn't released as a Ubuntu Lucid package yet; somatic-sniper1.0.2 is the latest. I'll let the developers know.