Read/write Excel files

From poking around in the Object Browser and the DataGridView documentation I get the impression that there is more than one way of interoperating with Excel.  I don't need continuous or interactive connection, but I do need to read and write .xls files.  I can operate in a model of Open, Read a bunch of cells, Close and Open, Write a bunch of cells, Close.

What is the simplest and best way to accomplish this?  It would be really nice if I could find a method that could be coded once to interoperate with all different versions of Excel.