We have been able to embed the the IronPython interpreter into an Excel
xll addin allowing one to write Python functions straight onto a Excel
spreadsheet which can then be used to evaluate the values of  cells.

This embedding is demonstrated in one of the 'Extra Examples' shipped
with the free and open source software xlw.

xlw ( v4 ) can be downloaded from here :

http://sourceforge.net/project/showfiles.php?group_id=45222&package_i...

The example was created as a demo of IronPython on a spreadsheet and is
intended to be extended by the user for his/her own needs.

If anyone would like to extend the example to be more 'sexier' and
contribute the result to xlw for shipping with next release ( 4.0.0 )
that would be great.