To make an iframe: use the following code:

<iframe src="http://domain or url" width="a number" height="a number"></iframe>


Here are a couple of iframes that I created for you, with the code for each right underneath.

<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRlnj4lYppuXKUw" width="430" height="420"></iframe>

 

 
<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRlm46fnOtA7GEQ&output=html" width="430" height="420"></iframe>

 
<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRlkBR9QaAqIpMw&output=html" width="430" height="420"></iframe>

<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRllK-SoSwE9WUw" width="430" height="420"></iframe>

 

 
<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRllPKj6svNFAFA" width="430" height="420"></iframe>

 
<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRlkv2YP-p6P7aQ&output=html" width="430" height="420"></iframe>

 
<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRlnFZ1kZtUvtRg&output=html" width="430" height="420"></iframe>

<iframe src="http://spreadsheets.google.com/pub?key=p_1RgTXrNRlnrPJhJuJYacA&output=html" width="430" height="420"></iframe>