In tools options under the general tab there's a secrtion called
Alternative startup file location.
set that to (for example) c:\my documents
Then....
create a new work book
and then save it into that directory and call it "macros.xls",
Create a new macro when it asks for it's storage location (dependant on
how you create a macro) save is into the spreadsheet you've just created
(ie macros.xls).
once done resave it *but* before you do save it hide the workbook
(window - hide).
This way everytime you open a new (or existing) spreadsheet the
macro(s) will available to you.
When you need to add or change a macro to the "macros.xls" spreadsheet
you'll need to unhide it, amke the necessary changes, re-hide and
save.
HTH, if you need to have anything more clearly explained please ask
Mr_Ben