In Disk Utility, use "MS-DOS (FAT)" as volume format. MBR partition map should work. Give the generated image file the extension .iso instead of .dmg. The file -should- then work easily with Windows.
How do I chose the volume format? After I click on "New Image", I'm supposed to chose Imagem Format (read-only / compressed / read-write or DVD-CD master) and Encryption (128 bit or 256 bit). I can't find "volume format" or anything about "partition map".
Think he was accidentally talking about hard drives. Just select DVD-CD master and use no encryption. I believe you can just rename it from .cdr to .iso and it will mount. It's been awhile since I've done this, but I believe that's right.
It didn't work for me. When I copy the "iso" file to the PC, Windows recognises it as a RAR file, even named as .iso Any other idea?
After transferring, what are you doing with it on Windows? Just double-clicking it? You either need to burn it or use something like Alcohol 120% to mount it on a virtual CD/DVD drive.
You can't just rename the disk image... One way to do it is like this: http://www.macworld.com/article/135728/createiso.html There are also some freeware tools if you're not comfortable with the command line: http://www.versiontracker.com/dyn/moreinfo/macosx/32275 And it's amazing how quickly you can find this out if you google.