Good news! You can now insert html using google sites new HTML, CSS, Java Script gadget.
Please bear in mind however that some scripts will not work, as I discovered this morning when I unsuccessfully added a twitter gadget (which is mainly js).... this apparently due to the code being tidied up by google's sweeping brush, however lets hope in time more complex code will be allowed ....
Even with this little hold back the tool is certainly handy and this is how you use it ....
Navigate to your chosen page > click on edit > where you would the html box to be > click on insert > select the html gadget from the list > add your chosen html and save
Screenshot of html gadget box containing code
Enjoy! B x
