Hi Lorna, long time no see. How've you been? Good, I hope. Anyway, I've been playing with the Google chart API myself in a few recent projects and I have to say that I too love it. Unfortunately, I can't say I find the API itself that easy to use: you'll have to know what chxt stands for, and it creates an unreadable query string.
So, do you know of a (simple) PHP wrapper API, that will generate the correct query string by using a DSL? I would definitely love that :)