Here's something I got a while back -
Instructions
Installation
No installation is needed. Just unzip the file contents and run the included Rasterbator.exe application. The application is wizard-like, which means it asks you questions and you click Continue button (or Back if you want to change what you previously answered). There are five screens with different options.
1. Select source image
In this phase you need to select the image you wish to rasterbate from your hard disk. Either enter the file name (with path, such as c:\images\snowman.jpg) in the box, or click Browse... to open the standard file dialog, which you can use to select the file. Note that the Continue button will be disabled if the file does not exist.
2. Select paper size
The rasterbated image will automatically be split onto several pages and in this screen you select the size of the paper you wish to use. Either use one of the predefined paper sizes (such as A4 or US Letter) and choose either portait or landscape printing (horizontal or vertical alignment of the paper), or use custom paper size. In the latter case, you need to input the paper width and height in millimeters.
3. Define output size
Using the paper size you selected, choose the size of the rasterbated poster you wish to use. You can define a specific amount of papers to both dimensions: width and height. The other dimension will be calculated automatically from the dimensions of the source image. The image size and paper consumption will be displayed on the page. Also, the preview image will show how the image will be distributed to different pages.
4. Set rasterbation options
In this screen you set up the preferred output options. The options are the following:
* Draw cutout line around rasterbated area (default value: on)
This option wil draw a dim rectangle around the rasterbation graphic of each page. The border will make it considerably easier to cut away the empty margins. If you plan not to cut out the margins, you should uncheck this.
* Dot size (default value: 10 mm)
Dot size defines the maximum size of the dots of the rasterbation. As a general rule, select small dot size for small output images and larger dot size for bigger output images. For a typical rasterbation job, good values are between 5 and 25 mm. Please note that dot size is the distance between centers of adjacent dots, as the dots may overlap.
* Color mode (default value: black)
The color mode affects the color of the dots in the poster. Black and custom color mean one-colored dots: the brightness is conveyed by using smaller or bigger dots. Multi-color includes the original color from the source image to the rasterbated poster.
5. Save rasterbation as
This should be pretty easy. The default value for the output file is the file name and directory of the source file, except that the file suffix (such as .jpg) is replaced with .pdf. If a file of the similar name exists, the suggested output file name will be suffixed with such a number that there exists no file the name.
Rasterbate!
Then, click the Rasterbate! button. The program will produce the output image. If you want to use other programs while rasterbating, check the "Rasterbate on low priority" option. This will slow down the rasterbating, but it makes other programs more responsive.
When the rasterbation is completed, you have the option to automatically open the produced image file (requires that you have a pdf reader in your computer system).
And for those curious to try it out -
http://the-rasterbator.en.softonic.com/download
