There are a few ways to do this. The first two involve setting your Pages document in File > Page Setup… to landscape orientation. I originally wrote this for Pages 2. In Pages 3 or 4, use the page layout mode for #s 1a & 1b.
1a - Use linked text boxes. This is easier done with the layout showing. First you need to add a page break to have two pages. Click in the body area & then Insert > Page Break. Now click outside the layout area to enter object mode & click the "T" in the tool bar or Insert > Text to create a text box & type something in it. This is to keep the box from disappearing if you click elsewhere & the text can be replaced later. If you already have some text to paste in you can just paste while in object mode & a text box containing your text will be created. You will now need to click outside the layout again & drag the cursor toward the text box to select it. You can now position the first text box in the lower right of your 2-page document. It is easier to see where it goes if you have the document set up with 2 columns. Click on the blue-outlined tab at the lower right of the text box to create a new of the same size & move the box to the upper left. Repeat for a box for the upper right & again for the lower right. You will now have 4 linked text boxes.
1b - Start as in 1a creating a 2-page document with 2 columns in landscape orientation. For this one you will use the body text area. Just type or paste your text in as normal, starting in the upper left. When you have your text done, cut all of the text in the first column (upper left), insert a column break after the last character on the now lower left column & paste the cut text after it in the now lower right column.
Neither one of these will let you automatically use page numbers because Pages "sees" each page & you actually have 2 pages per page.
2 - Since you're still using Tiger, you can use
Cocoa Booklet to create a booklet with any number of pages (best in a multiple of 4).
For a folded letter-size booklet start with your Pages document in Legal size & larger than normal font size. Export the Pages document to a PDF & then drag the PDF to the icon of Cocoa Booklet. It will create a new PDF in booklet form.
CocoaBooklet no longer works in Snow Leopard.
