You can export to Excel, but you will have to create an transform file and apply it to the XML that is saved from the form.
Try this:
1. Open your Excel file, go to File -> Save As, choose ExcelML to save the Excel file as an XML file.
2. Open the XML file created in step 1 in Visual Studio and insert XSLT functions and change the file extension to map data from your form into the ExcelML format.
3. Apply the transformation from a file that you have saved off from your form.
I hope this helps, I know it's a little vague, but it's been a while since I've done this and it's not the easiest thing to do.
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge