Hi Günther!

The chicago project aimed at building a shared library to handle reading
and writing excel files. If you don't want to write an excel
importer/exporter in Squeak yourself, you could use the library through
FFI(3). I don't know how far they've come and what the status of the
project is, but it might be worth a look(1). Here(2) are also some
pointers to general info about the excel file formats and
implementations in various languages.

Hope this helps,
	Alex

(1) http://chicago.sf.net
(2) http://chicago.sourceforge.net/devel/docs/excel/
(3) http://minnow.cc.gatech.edu/squeak/1414