pass textbox values of one page to html template of another page

i have some textboxes.. when 'preview' button is clicked it goes to another page, preview.aspx which contains an html template.. i need to replace the textbox entered values inside the template.. how will i code it using asp.net? The html template is

preview.aspx .....

<table width="450" border="0" cellspacing="0" cellpadding="0" class="bg" bgcolor="red">
                                        <tr>                                            
                                            <td width="90" valign="top" class="bg" bgcolor="#ffffff">
                                                <h2 style="width: 642px">&nbsp;&nbsp;&nbsp;&nbsp;<i><font color="#333333" face="Geneva, Arial" size=2.5>From:</font>&nbsp;&nbsp;
                                                    [mg-from]<br/>
                                                &nbsp;&nbsp;&nbsp;&nbsp;<font color="#333333" face="Geneva, Arial" size=2.5>To:</font>&nbsp;&nbsp;&nbsp;&nbsp;
                                                    [mg-to]<br/>
                                                &nbsp;&nbsp;&nbsp;&nbsp;<font color="#333333" face="Geneva, Arial" size=2.5>Subject:</font>
                                                    [mg-subject]</i></h2>
                                            </td>
                                        </tr>
                                    </table>

need to replace [mg-from] with txtfrom.text of the first page......how will i code it using asp.net ....... pls help me ....