I have been using a program called Spreadsheet Converter to convert
Excel spreadsheets to be viewed on the web. There are some functions
that are not available, but all in all it has been very effective. If
you would like to see some samples of spreadsheet conversion to html
check out the following links:

http://www.business-analysis-made-ea...lculation.html
http://www.business-analysis-made-ea...alculator.html
http://www.business-analysis-made-ea...on-Matrix.html
http://www.business-analysis-made-ea...ine-Graph.html
http://www.business-analysis-made-ea...Pie-Graph.html

I use the object tag to include the rendered html file within a parent
html file.