Joomla-latest-component-example is a project mainly written in PHP, it's free.
A hello world example of the latest version of Joomla
Just a simple Joomla 1.7 Hello World extension
The idea is to keep a working Hello World component example that always works with the latest version of Joomla
Use phing to install package and install it on your site.
Phing: If you don't have Phing installed, get it here. From the repository root:
phing -f build/build.xmlThat should create a folder at phing/packages with an installable zip.