How can I install MonoDevelop v4 on 12.04?

Installing Mono develop 4 on 12.04 precise

Option 1: Compile Git version from source

First uninstall your current version of mono develop with the software centre then from the terminal run following commands:

sudo apt-get install build-essential automake checkinstall intltool git
sudo apt-get install mono-complete mono-addins-utils gtk-sharp2 gnome-sharp2
git clone git://github.com/mono/monodevelop
cd monodevelop
git checkout monodevelop-4.0
git submodule update --init --recursive
./configure
make
sudo checkinstall

Option 2: Installing from PPA

Un-install current version first

sudo add-apt-repository ppa:keks9n/monodevelop-latest
sudo apt-get update
sudo apt-get install monodevelop-latest

From terminal run:

monodevelop

The ppa from the first answer

ppa:keks9n/monodevelop-latest 

seems to be outdated.

If you want to use the latest version ( 4.2.2+ ) with the latest runtime and so on, I suggest to use this new ppa:

sudo add-apt-repository ppa:ermshiperete/monodevelop
sudo apt-get update
sudo apt-get install monodevelop-current

After this you will have monodevelop installed in the /opt/monodevelop. To start the IDE use the following script:

/opt/monodevelop/bin/monodevelop-launcher.sh