Using XP Pro and Excel 2002/3

I have been asked to provide an Excel spreadsheet
that people can use as a purchase request form.

Some of the fields will contain data that is already
defined. For example ...

Project Name. A list of project names exists.

Commodity codes and associated description.
A list of codes and their descriptions exists.

Is there some way that I can provide a drop down
for cells? Like a combo box in Access for instance?

I realise I could create a form with VBA behind it,
but I was wondering if that sort of functionality
could be provided at the cell level, without going
to the complication of a form.

Thanks,
Roy