Sending HTML output from MySQL query to Excel

I searched the archives and read the postings about using header("Content-Type: application/vnd.ms-excel"); to send tables dynamically constructed from a MySQL query to an excel spreadsheet, but when I tried it (using IE 6) all I got was a picture icon in the top left corner of the screen and no output anywhere. I know the query works, and I can create the tables just fine in HTML when I don't add any headers - so how do I get this to go into Excel? Thanks, -Lisi