Richtextbox in sharepoint

<%@ Register TagPrefix="SharePointSD" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral,PublicKeyToken=71e9bce111e9429c" %>


<SharePointSD:InputFormTextBox runat="server" ID="RichTextBox" ValidationGroup="CreateCase" Rows="8" Columns="40" RichText="true" RichTextMode="FullHtml" AllowHyperlink="true" TextMode="MultiLine" />