Oversize color prints can be made from virtually any application. Even if the document is not created in a large size, it can be scaled for final output at a larger size. Illustration programs such as Illustrator and Freehand produce excellent results. Object-oriented graphics are ideal for oversize prints because they can be output at any size without concerns about resolution. For best results, scanned images should be saved in the EPS format.
Oversize files can take up a lot of disk space.
If you are going to be transporting the file for printing, you need to plan ahead. Keep all related files on the same disk. This makes it much easier to ensure proper graphic linking and output. If you are submitting your file in a PDF or PostScript format, be sure to embed all fonts. Don't over design.