Thank you so much for your reply. Can you explain why this won't work? How can I tell which timers are being used by the servos? It looks like I can only use Timer 1 or 2 for the Tone function on Uno (which I am using). How many timers are there? Any way to specify the servos use other timers? So this means I cannot have a TV-remote controlled robot that has two servo wheels using the Uno and have it play a little tune using Tone? If I use the Mega, will the timers be allocated appropriately or do I need to alter the library? I'd like to know a little more info because I am leading a group of kids on this and want to explain to them. Don't worry, I am not charging these kids for this 
. I will try implementing your other method for playing a tune. How do you create different frequencies with it? Do you think I could play a simple tune ok?
Thanks again.