Word 2003? If yes:
When you create a booklet, it's best to start with a new,
blank document so that you have better control over the
placement of text, graphics, and other elements. You can
add a book fold to an existing document, but you may have
to reposition some elements once the book fold is in place.
Start a new, blank document.
On the File menu, click Page Setup, and then click the
Margins tab.
In the Multiple pages list, select Book fold.
If your document is not set to landscape orientation,
Microsoft Word sets it to landscape.
In the Inside and Outside boxes, type or select the amount
of space you want for the inside and outside margins
(margin: The blank space outside the printing area on a
page.).
If you need even more space along the fold to accommodate
binding, type or select the amount of space you want in the
Gutter box.
In the Sheets per booklet list, select the number of pages
you want to include in a single booklet.
If the number of pages in the document exceeds the number
of pages you select for a booklet, Word prints the document
as multiple booklets.
Select any other options you want in the Page Setup dialog
box.
Add text, graphics, headers or footers (header and footer:
A header, which can consist of text or graphics, appears at
the top of every page in a section. A footer appears at the
bottom of every page. Headers and footers often contain
page numbers, chapter titles, dates, and author names.),
and other elements to your document as usual.
The above response is from Word Help, search on "booklet"
