basic vbe question

Hi,

I've just started playing with VB for Excel and I have some very basic question which I have not been able to find the answer on the internet.

Could anyone help me please.

The questions are the following:

I have written a visual basic program to process some Excel data. I made it available to all open workbooks but when I closed Excel I lost it.

How do you save the VB code so that it is independent of any workbook?

What file extension should it have?

Where should I save it, I think in folder XLSTART?

I will really appreciate any help.

Thanks in advance.
leon