How do I make very large maps? Which software should I use?

[Quabbe]

photoshop has a limit of 2 gigs (at least up til CS3 which I use)

You can safe your large files as .psb instead of .psd. That should be already included in CS3.

That way my largest file (12k x 12k px) with tons of layers had 5,xx gb.

[Razyda]

Hello,
This is my first training map.
Done mainly thanks to training on this site
Thanks all
Any feedback would be appreciated

[neelhtak_backwards]

Thank you for your suggestion of using .psb file formats. I had been previously working in a 8000x8000 odd pixel document with something close to 700 dpi. Although my computer is powerful, for some reason it just couldn't handle the psd file well - even though it was only 300 odd MB's. As soon as I saved it as a psb everything just loaded and worked far more efficiently. Thanks!