The Inquirer is a British computer news Web site that I like to visit every day for its British-style reporting on computer news.
A recent review of Digital Camera Poster Creator made write an email to the author:
Some software packages and some printer drivers include that functionality.
Visio software, for example, creates posters. Just copy and paste the image into a Visio page, and then use the page setup options to specify the number of pages to print over.
My HP PhotoSmart printer's driver has a similar feature that works with any software program: select the poster option, and then specify the number of pages to print over. A preview lets you see how it works.
Created a nice poster for my dad of a picture he took of a dozen hummingbirds at a feeder.