Excel can be saved as an XML, which I would recommend.
Actually, I'm in the works with a project right now thats very similar, I take a spreadsheet containing employee's numbers, firstname and last name and insert them into a database. I use the php DOM functions to do this.
Sorry, as of right now though, I haven't started the work with the XML from the spreadsheets yet, just the word documents. In the near future I'll have a better answer for you.
Now, if you simply want to display as html, look at using an xsl stylesheet instead, the xml guys can help you with that one. If you need to extract and use the information with php, its dom your after, which I will be able to help you with.
Looks like your after an xsl. Once you create one, it would be simple to use either as an embedded stylesheet (browser specific) or by server side conversion (universal).