There's an example in an article that I wrote some time ago:
http://www.ftponline.com/vsm/2002_07/magazine/columns/aspnet/page5.aspx
RegisterArrayDeclaration Inserts an array declaration into the HTML code,
including the <script> tags. Accepts both the array name and a
comma-separated list of values as a string.
RegisterClientScriptBlock Inserts a block of client-side code within the
HTML form. The first parameter is an identifying name for the block as a
string. The second parameter is a string containing the script to be sent to
the client. You must include the <script> tags.
RegisterHiddenField Inserts a hidden input field with the HTML form. The
first parameter is a string that provides the input control's name. The
second parameter, also a string, is the field's initial value. In the
rendered content, this field appears just before ASP.NET's hidden
"__VIEWSTATE" field.
RegisterOnSubmitStatement Inserts an OnSubmit attribute into the page's
<form> tag and the script to be called as its value. The first parameter is
a unique identifier for the script as a string. The second value is the
statement or function called. This creates inline code, so no <script> tags
are allowed.
RegisterStartupScript Inserts a script block just before the closing </form>
tag. The first parameter is a unique identifier for the script as a string.
The second parameter, also a string, is the complete script including the
<script> tags.