According to the page http://www.google.com/support/cloudprint/, I should now be able to print gmail mails :
Answer taken from this page:
How do I print to my Google Cloud Printer?
+ The steps you take to print will vary from application to application.
- On Chrome notebooks, ...
- On Gmail and Google Docs for mobile, click the menu in the top right corner and select Print.
click the menu in the top right corner and select Print.
I don't see such a button or looking at the wrong place.
UPDATE - ADDITION
Because I don't think this should qualify as a new question: I want to add this to my original: what native Android applications support Google Cloud-Print ?