I also think this is the best option for him.

Correct. 4x posts is DEFINITELY enough to get FTP access....

What?

Er, I posted in the wrong thread. The FTP servers too slow for me. BTW, any ISO for Mac OS X 10.8 GM?

No, since the GM is most likely the final one, which means it won't end up here until it's abandonware.

macdrive is a great option for just using dmg on windows btw, for future reference

Have you tried Catacombae DMGExtractor

http://catacombae.org.preview.binero.se/dmgx.html

It's Java based so is platform independent it also supports many of the dmg compression formats.

Try TransMac.

I've done this many times. Change the extension from .DMG to .ISO

@Mustafa Can
With Transmac you'll lose the bootability (if it isn't a word it is not).

If you use Transmac I should recommend you using an oldfashioned external bootable image/drive, i.e. rBoot and iBoot.
Just google "rboot" and you'll find a way to use it

Welp. I actually have experience with this from downloading from the Apple website to get the driver set for Windows 7 for a friend.

Downloaded the file (in dmg)
converted it to img with dmg2img..
Aaaanddd... STILL unusable. I was stumped for a while, but then I found out that the data was compressed with a cpio compression on an unlabeled binary. Lovely. I unzipped that, and I got to the iso in the directory. Why did Apple make their packaging format so obscure..?

It's obscure on windows: I suspect that once you extract the dmg you're left with something without an extension, which puzzles the operating system.
On any unix system you learn that the extension is not a good file format identifier (if only MS added a "file" command to the command prompt...).

Try directly open the DMG file with 7-zip, if you see a "Mac OS X Install ESD" folder only or several files named as "0.ddm", "1.Apple_ISO" or such, you can close 7zip, open the dmg with UltraISO and click "Tools->Format Convert" to convert it into an ISO.

But if you see an "Install Mac OS X Mountain Lion.app" folder, go to \Install OS X Mountain Lion.app\Contents\SharedSupport\InstallESD.dmg, extract it somewhere and open it with 7z again, find a \InstallMacOSX.pkg\InstallESD.dmg file and extract it. Use UltraISO to process this dmg, which is what you will need.

UltraISO for win 100% works fine for me (snow leopard *.dmg, mountain lion *.dmg), Tools->Convert

ig does not work for your *.dmg some bad (crap) is this dmg ...