Does this cost money? And what does my asp.net application need to be/need to have to use AJAX?

I have a calendar control that I wrote based on someone else's code. You can't easily skip through years. So when it defaults to today's date, if you want today's date last year, you have to hit the arrow button 12x (or manually type your desired date, but that defeats the purpose of having a calendar control!)

Thanks.