someone found a solution to this, all credit goes to ArchDevil at designtechnika.com
You'll need to download Transmac
"1.first open transmac
2.on second pane i mean "mac folder" pane click "mac drive" pulldown menu.
3.select "volume image file" than locate your .dmg file
4.in listbox select the files you want to extract from .dmg file..
5.right click on them and select "copy selected"
6.paste it into "pc files" pane "
i've tested it on XP, and it works with .img files and .dmg files also.
After you save them, you can convert them with iconshop.
Edit:Great,volume 5 of Gort's iconsare converted to .ico format , 128X128
/me was a bit sceptical, it coming with a hefty pricetag, for a lot of features I'll never use... the <1.5 Mb file limit and other limitations kinda comfort me though, it being a lucky coincidence I can use it for some minor and seldom operations (dunno if that is really morally right...).
If I'll need to use it really often, I'll start looking for a more comforting solution, but for now my collection of BeOS icons is complete .
TransMac doesn't work with some dmg files.. i've been using it a while.. decompressing RAD.E8's icons.. but some never icons sets in dmg files can't be decomressed with Transmac.. don't know why yet though..