Is there a easy way to insert source code with highlight in Google Docs?
Not directly but there is an easy way to do it.
You can use the online Colorer-take5 HTML generator to produce the highlighted code. Afterwards just copy/paste it into your document, but don't forget to change the font to
Courier New and probably reducing the size of it and you're done.
Here is an example for Java code and using the Eclipse style: