What I've done is used Highslide with an IFRAME and an ASPX page. It doesn't get blocked by pop-up blockers and works well.
http://vikjavev.no/highslide/
In addition, you could use the ModelPopup from the ASP.NET AJAX Control Toolkit.
http://www.asp.net/AJAX/AjaxControlToolkit/Samples/ModalPopup/ModalPopup.aspx
That covers the display of the popup. To access the data you could use something like I do in my modules to get the data to lookup from the link's querystring:
' Get data
Dim mySqlDataAdapter = New SqlDataAdapter("SELECT Field1, Field2 FROM TableName WHERE ParamName = @ParamName ORDER BY Name", ConfigurationManager.ConnectionStrings("DataConnectionString").ToString())
mySqlDataAdapter.SelectCommand.Parameters.Add("@ParamName", SqlDbType.Int).Value = Request.QueryString("campground")
Dim myDataTable As New DataTable
mySqlDataAdapter.Fill(myDataTable)
If myDataTable.Rows.Count > 0 Then
....