In earlier versions of Ubuntu, actually up to 10.10, a Mac OS X transformation pack was available for Ubuntu users (based on GTK 2.*) but now the Ubuntu 11.10 (the latest stable version) or 12.04 LTS (only alpha versions are available right now) as well as other Ubuntu derivatives such as Linux Mint, are based on GTK 3 – so the transformation pack doesn’t work anymore. Both of the desktop – Unity (The default interface in 11.10) and Gnome 3 shell are quite popular. I’ve already covered a post about getting a Mac like look in Ubuntu 11.10 with Gnome shell desktop so this article is about Unity desktop.
mac-osx-theme-ubuntu

If you want to make Ubuntu 11.10/12.04 look like Mac OS X Lion, then you need to install few basic things -
  1. GTK Theme
  2. Icon Theme
  3. Cursor Theme
  4. Gnome Tweak Tool (To manage themes)
  5. A dock application (Docky or Cairo Dock)
A cool snapshot – exploring Cairo Dock effects (using OpenGL, although you may choose to ‘no OpenGL’ version of Cairo Dock if the graphics performance of your computer is poor), of  my desktop after install above stuffs :
mac osx-theme-in-unity

Installing Mac Theme by ‘MBoss’ Packages

First of all – download the theme package (it contains theme, icons and cursors) and extract it to appropriate locations as specified -
1. Download Mac OS X GTK Theme package and extract it to ~/.themes
2. Download the Mac OS X Icon theme and extract it to ~/.icons       (create that directory if it doesn’t exist)
3. Download Mac OS X Cursor Icon theme and extract it to /usr/share/icons
For extracting cursor icons to usr/share/icons location, you need root access while browsing with nautilus
gksu nautilus
and finally you may need to change the permission settings to make it accessible also by a non root user. (By default it may be assigned root permission only).
Change Directory Permissions
Install Docky or Cairo
If you like Docky then install it from Ubuntu Software Center or execute (as it’s there in repository by default) -
sudo apt-get install docky
On the other hand – if you want to try Cairo Dock (as seen in screenshot) then execute these commands
sudo add-apt-repository ppa:cairo-dock-team/ppa
sudo apt-get update
sudo apt-get install cairo-dock cairo-dock-plug-ins
cairo-dock
Gnome Tweak Tool is very handy for changing themes or tweaking other settings of Desktop so If you haven’t already installed it Gnome Tweak Tool then install it by executing the command -
sudo apt-get install gnome-tweak-tool
gnome-tweak-Tool-settings
Now, open Gnome Tweak Tool and select Mac_OS_X_Lion_Theme  - as indicated in above snapshot. Then, start Cairo Dock or Docky whatever you have installed. That’s all I hope you are enjoying the cool look of Mac on your Ubuntu 11.10/12.04 computer. Have Fun :) – let me know if any problem occurs.
Besides Gnome Tweak Tool, you could also use ‘Ubuntu Tweak‘ – a small application to tweak/customize desktop in easy way.
ubuntu Tweak
To install Ubuntu Tweak, execute the following commands -
sudo add-apt-repository ppa:tualatrix/next
sudo apt-get update
sudo apt-get install ubuntu-tweak
Thanks to MBOSSG for his art work – i.e Mac OS X Theme, icons and cursor themes.