Licensing
All the code here is covered by the PHPGuru license. A short summary is that for any sort of commercial use there is a small one-off licensing fee to pay, and for charity and educational use there is a reduced license fee.
You can read more about licensing here (where there's also a link to Google Checkout).
Looking around at what's available, I've found this. It's much better.
CanvasText: How to get text on your canvas (HTML5)
A Javascript library that allows you to write simple text to your canvas.
The source that produces this text is:
<script type="text/javascript" src="CanvasText.js"></script>
This pulls in the CanvasText library. And this...
<script type="text/javascript">
<!--
CanvasText(document.getElementById("myCanvas"), // The canvas object
'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789', // The text to write
10, // The X position (the bottom left corner of the text)
20, // The Y position (the bottom left corner of the text)
10); // The text height in pixels
// -->
</script>
...simply draws the alphabet. Wonderful eh?
Note: This library is quite large at around 12k, so you may want to gzip it, for example mod_gzip should do it automatically for you. If you're not using Apache, you're on your own... :-) The gzipped version comes out at under 2k - quite a reduction.