You can also just create a form and modify it to be like this:
Code:
<form name="agreeform" onSubmit="return defaultagree(this)">
Rest of your form here<br>
<input name="agreecheck" type="checkbox" onClick="agreesubmit(this)"><b>I agree to the above terms</b><br>
<input type="Submit" value="Submit!" disabled>
</form>
<script>
//change two names below to your form's names
document.forms.agreeform.agreecheck.checked=false
</script>
<p align="center"><font face="Arial" size="-2">Free DHTML scripts provided by<br>
<a href="http://www.dynamicdrive.com">Dynamic Drive</a></font></p>