The following applies to ps files, not pdf files. The institute for architecture can print A0-size for a small fee (I believe). This (in Norwegian) describes how to split an A0-file into 16 A4 pages, but there are some errors. You need to change the brukposter script (it should read "./poster" instead of "poster"), and you need to give yourself execution rights for the brukposter script by running "chmod +x brukposter". Then you can run the script using "./brukposter input.ps output.ps" (note the "./"). It runs for a while and generates a lot of output. See also this page and in particular this quote:

I had a lot of trouble with included EPS graphics, which largely went away when I normalised the EPS files with the eps2eps utility which is part of the Ghostscript distribution.