Some friends of mine at San Jose State in our Operating Systems class find themselves in need of a Linux system. Some of them have Mac's, some PCs, both of which support and allow virtualization. But the easiest way is probably to use Amazon Web Services Elastic Compute 2 service. This allows creation of a Linux system in the cloud with all the software they need, and if they create the right level, it can absolutely free. See the below chart for the offer as of this writing.
1) Signup for AWS.
Go to http://aws.amazon.com/ and click the "Create a free account" button.
2) Take the Linux Virtual Machine tutorial, if desired.
3) Create a new linux VM
NOTE: Be sure to close your instance when done, or the billing may accrue (you can wind up spending for something that is free!!).Start by signing into your new account on the AWS Management Console.
4) Connect to your new instance.
NOTE: Be sure to close your instance when done, or the billing may accrue (you can wind up spending for something that is free!!).Once your new instance is running, create some SSH keys and connect!
5) Install compilation tools
sudo yum groupinstall "Development Tools"