CRYPTO7  Version 2.0.6 is out, and it rocks. Without this I could not have backed up my Win XP volume into 1 image file like you can with HFS/HFS+ volumes and bombich's carbon copy cloner (another highly recommended backup app). Unfortunately it does not work under 10.4.x.  
(Version 2.0.5)

CRYPTO7  Awesome program... does it what it says, doesn't require too much RAM for it (but I guess that's relatively speaking if you have 8 GB) and it's the only thermal program I can find that has all the temps w/out installing some ugly hack or startup item.  
(Version 4.6)

CRYPTO7  Okay, at least in 10.4.10 these are the same:

hdiutil convert /path/to/filename.dmg -format UDTO -o /path/to/outfile

and

hdiutil convert -format UDTO -o /path/to/outfile /path/to/filename.dmg

DMG Converter (http://sunsky3s.s41.xrea.com/dmgconverter/index.html) can create ISO filesystems. But it cannot CONVERT images to ISO filesystems, only make new images using it. But the Terminal command "hdiutil" can with the "makehybrid" verb. Open Terminal and type "man hdiutil" to see this; tap space bar or return to get down to VERBS (specifically convert and makehybrid). The syntax is:

hdiutil makehybrid -o [options]

[options] are -hfs, -iso, -joliet, and -udf. So first drag a .dmg to your Desktop. Then open Terminal and type:

hdiutil makehybrid -o ~/Desktop/[new_image_name] ~/Desktop/[source]

and hit Enter. [source] can either be a directory or a disk image. So if you mount the image first and THEN use DMG Converter, "converting" and "making" a new disc image from the mounted volume is the same thing... But the nice thing about the hdiutil Terminal command is that "By default, if no filesystem is specified, the image will be created with all four filesystems as a hybrid image." So don't specify -hfs, -iso, -joliet or -udf and your image has all 4 filesystems! I tried it on a 458 MB .dmg and got a hybrid .iso that was 530 MB in size. Compared to the 592 MB ".iso" file that was actually a .cdr made with "hdiutil convert" -- and only had the single HFS+ filesystem -- I'm much happier w/ the true ISO that is 60 MB smaller and has 4 filesystems! I'm beginning to like UNIX more and more... BTW Damage Isolation DOES make .ISO images which can be burned using Sonic, etc. and other windoze apps, but just beware that the burned CD has only an HFS+ filesystem.  
(Version 1.4.2)

CRYPTO7  This does the same thing as:

hdiutil convert /path/to/filename.dmg -format UDTO -o /path/to/savefile

but neither that nor this makes an ISO9660 *filesystem*... they both are still Mac OS Extended (HFS+). I can use neither resulting image on WinXP!! Crap... to the person who asked about .dmg, you can't just rename those b/c they are compressed. If you make a .cdr ("CD/DVD master") and rename it .iso, that will burn in Windoze programs, but the damn volume is still hfs+ and therefore not readable when you put the disc in a PC optical drive. I typed "man hdiutil" and there is a "filesystem -iso" but I can't figure out where to put it in the command b/c I think Apple changed the hdiutil syntax. :(  
(Version 1.4.2)