Phil,
I have been reading on moon and star shots and came across this video.
http://www.youtube.com/watch?v=ncILazaR18g
Not sure what your broadband speed is so I will paraphrase.
The Canon sx40 will not allow the ISO to be set higher than 100 for exposures longer than 1 second. I think you should be able to get shots of the moon but some nightime shooting will be hampered by this.
I have not looked into this in any great depth so I may br wrong but I saw it and thought of you.