deploying vba application on a network

Hi everyone,
I wonder if someone can point me in the right direction on this one?
I have a client for whom i have written a vba application - it currently runs on two separate PCs. The client wishes to run it on five networked PCs.
my initial thoughts are these: put all data workbooks on the network shared drive and make them shared books. Then install my VBA code workbook on each PC? Am I correct in thinking that the application needs to be on each PC as this where the each version of Excel resides.
One added complication - there is a mix of 2003 and 2007 office versions.
Any advice would be much appreciaated
Regards
Alan

thanks for your help Roy
Alan