You should have a lawyer to do this for you. You can search on google and you will find free samples. I found this one:

http://contracts.onecle.com/blackbaud/client.support.2003.08.01.shtml

>hi to all
>i need some Document regarding Software Maintanence COntract.
>if any one have any website address please send me link on my
>email address.My email id is m_naya52@hotmail.com
>
>Thanks in Advance
>
>
>Best Regards
>Mazahir