Start and access Amazon EC2 micro ubuntu instance.

Logon/sign in: http://aws.amazon.com/ec2/

Start an ubuntu micro-image, Eg:
ebs/ubuntu-images-milestone/ubuntu-oneiric-alpha2-amd64-server-2011*** (ami-00b14b69)

create a keypair:_ something.pem

change the permission of something.pem to 400:
sudo chmod 600 something.pem

create security group:
- open ssh, tcp - in the security group, by editing/adding rules.

access the virtual machine using ssh, using public DNS of instance:
For ubuntu machines, default user is ubuntu:

So, access it like:
ssh -i something.pem ubuntu@ec2-67-202-**-***.compute-1.amazonaws.com

To install gcc/openmpi

sudo apt-cache search make g++ libopenmpi-dev openmpi-bin openmpi-doc build-essential gcc-multilib libstdc++6
sudo apt-get -y update
sudo apt-get -y install make libopenmpi-dev openmpi-bin openmpi-doc build-essential gcc-multilib libstdc++6