If you need to hide the 'Site Actions' dropdown for some users but not all of them (administrators must see this dropdown), you've to edit the master page and add a SPSecurityTrimmedControl that contains your SiteActions control:
SharePoint:SPSecurityTrimmedControl ID="spSecurity" runat="server" PermissionsString="ManageWeb"> SharePoint:SiteActions CONTROL /SharePoint:SPSecurityTrimmedControl>
If you add a SharePoint:datetimecontrol and you have problems woth the render of this control you've to add a link to the datepicker.css class in the iframe.aspx.
This layout is located in the '/layouts' folder of the MOSS installation.
link rel="stylesheet" type="text/css"href="/_layouts/1033/styles/datepicker.css"/ script> layouts/1033/styles/datepicker.css"/> Date Picker