I need to develop a website that will allow the users to upload Excel 2003
files that need to be read and the information stored in a database. The
site will also produce reports in Excel format. This is no problem to do
with a desktop app as long as the user has Office installed.

My question is what is the bare minimum that I need to install in order to
get the capability to read/write Excel 2003 documents? I don't want to put a
full installation of Excel on the server if it can be avoided. Is there
another way? Will it be any different with Excel 2007?