Yes, you too can have a Poor Man's Mac, thanks to Dreamlinux, CompizFusion, Avant (AWN) and legally questionable icons and wallpaper. I don't recommend using copyright material, you do so at your own risk, this is just an explanation of how it's done....mostly because I keep getting asked. Notice I'm not hosting any of that material myself. 
This guide is for Dreamlinux 3.1 users who have chosen GNOME. This guide is strictly to change the look of the Desktop Environment, not the entire system.
Background:
http://appleology.com/images/space-desktop.png
That wallpaper is 2000x1250 so you can resize it to whatever you need for your resolution. Place it where ever you keep your wallpapers, then right click on your Desktop and choose "Change Desktop Background" and then click on the Add button to locate your wallpaper and select it.
Icons:
http://www.osx-e.com/downloads/icons/ileopard_icons_pack.html
or you can use these instead...
http://catalin-v.deviantart.com/art/298-Leopard-Icons-61399795
You can just put the extracted icons in your Home folder in their own folder called Icons.
Dock:
1.) You will need to enable the 3D graphics drivers of your video card, if you use an Nvidia card just go to: Applications > System Tools > Easy Install. Then under the Drivers/Multimedia Section click on Nvidia Install and follow the instructions.
2.) You will need to enable CompizFusion. Go to the DCP-Control Panel and click on En/Dis(able) CompizFusion icon to do so. Have it start at startup.
3.) Now you can use the AWN dock (which looks like the Leopard dock) instead of the Engage Dock. Go to the DCP-Control Panel and click on AWN Manager to add new launchers to the dock using the OS X Leopard icons you downloaded.
Changing the DL logo to the Apple logo in the Menu Bar (Applications/Places/System), and, changing the trash can icon:
(note: personally I think the Dreamlinux logo looks a thousand times cooler than the Apple logo, just my two cents)
Using the Root File Manager in your dock, go to:
/usr/share/icons/Go_Dream/scalable/places
In that folder you will find the icons named "start-here.png", rename it to "start-here2.png" so you don't overwrite it.
Also in that folder you will find an icon named "user-trash.png", rename it to "user-trash2.png" so you don't overwrite it.
All other logos and trash icons are linked to these two files, so when you change them, they will change system-wide.
(of course, don't include the quote marks)
Go to the folder where you put the OS X Leopard icons you downloaded, find the empty trash can icon, and rename it to "user-trash.png" and make sure it is sized to 128x128, then place it on your Desktop.
You can grab any Apple logo you want to use online and size it to 128x128, then rename it to "start-here.png" then place it on your Desktop.
Now drag those two icons into the folder
/usr/share/icons/Go_Dream/scalable/places
Again, go to the folder where you put the OS X Leopard icons you downloaded, find the full trash can icon, and rename it to "user-trash-full.png" and make sure it is sized to 128x128, then place it on your Desktop.
Using the Root File Manager, go to:
/usr/share/icons/Go_Dream/scalable/status
In that folder you will find an icon named "user-trash-full.png", rename it to "user-trash-full2.png" so you don't overwrite it.
Now drag that icon from your Desktop into the folder /usr/share/icons/Go_Dream/scalable/status
You may not see a difference until you restart or log out and log back in.
Now go to: DCP-Control Panel > AWN Manager > Applets and add the Trash Applet, this will put it in your dock.
Panel Icons:
If you want to change the icons for your panel at the top of the screen, using the Root File Manager you have to go to:
/usr/share/icons/Hi-Dream/22x22/apps
There you will see icons named "nm-device-wired" and "nm-signal" both have numbers following them and more than one icon. Copy these icons to your Desktop. Then rename the icons in /usr/share/icons/Hi-Dream/22x22/apps something else so you don't lose them, then use GIMP to greyscale the icons on your desktop you just copied (and perhaps adjust the brightness and contrast) to make them look black like the mac panel icons. Once that's done, move them back into the /usr/share/icons/Hi-Dream/22x22/apps folder.
Follow the same process for the Bluetooth icon if you need to use it, that panel icon is also in the /usr/share/icons/Hi-Dream/22x22/apps folder.
You may not see any change until you either restart or log out and login again.
Panel Background Color:
Last but not least, changing the panel background color. Right click on the panel at the top of the screen in an empty spot and select Properties. Then click the Background tab, then click the part that says Solid Color then below it click on Color, then enter this where it says Color Name: #C6C7CC
Click OK, then click Done. Keep in mind, with different monitors and different graphics cards, this may or may not look like the right color to you, feel free to experiment.
If you wanted to get a more rounded/gradient look you could always add a panel background to get the desired effect.
note: I did not change the panel background color in the screenshot, it was an after thought.
Remove Icons From Desktop
To get rid of any unwanted desktop icons (not in the dock), just open a terminal and type in:
gconf-editor
Then make your way to: apps > nautilus > desktop
From there you can uncheck the boxes for any icons you do not want displayed on your desktop.
And that's the way you do it!
Again, I do not advise using copyrighted graphics, there are free alternatives out there that are very similar. Try http://www.gnome-look.org and find something just as good. This tutorial is here strictly for the purpose of knowing how to do it. You could use this same tutorial to make graphical changes without using copyrighted materials.
