You can download PDFCreator from the authors website.
When you install the program it does two things. Firstly it installs a print engine on your computer. If you look at Start > Setting > Printers and Faxes you will see the PDFCreator icon sitting alongside your other installed printers.
The Second this PDFCreator does is install an Icon on your desktop that opens up a dialog box.
This is called the PDF-Print monitor, but it is much more than that, it allows you to perform quite a lot of functions, not the least of which is the ability to combine different PDF files together to form a multi page PDF document.

Using PDF Creator could not be easier, you simply choose the 'print' option from any windows application and then choose PDFCreator as your printer and click the Print button. You will then be prompted to fill in a few details and settings finally leading to the creation of a PDF document.

Using the the PDF-Print monitor is a little bit more involved but easy when you know how. For instance combining PDF documents you need to follow the following steps.

First double click on the PDFCreator icon on your desktop.

Next from the main menu choose Document > Add You will see a pop up dialog where you can choose the first file you wish add. Please Note: The dialog box defaults to PS files so you need to select All Files from the file type selector. Then you will see the PDF,PS or EPS files that you wish to add.
Choose a file and a dialog box will pop up prompting you to proceed with the file, at the bottom of the dialog you will see a button that says Wait - Collect, click that button.

You can then use the Document > Add command from the main menu and add as many documents as you wish

Once you have compiled your list simple choose Document > Combine all and the choose Document > Print to save the combined multi page document.

PDF creator also gives you the option to save files in PDF/A-1b, PDF/X, PS,EPS, png, jpeg,bmp,pcx,tif, txt, psd, pcl, raw and SVG. That's a very impressive list and adds a great deal of functionality to any windows application. PDFCreator is another program to use Ghostscript as its conversion engine so I know from experience that the quality of the output is very high.