Here are a few things that helped me settle in when I switched over from a PC:Application installing process
You download disk image (.dmg files).
You mount the disk image (by opening the .dmg file).
A disk should be mounted on your desktop (its usually a white icon)
All the contents of the application should be neatly packaged into a single folder/icon.
Drag the folder/icon into your Applications folder so its saved on your HD.
Eject the disk (being a power user, you can just click on the disk and push Command-E. There are even faster ways via an amazing app called Quicksilver).
*Don't think of the process as "installing the app". Its more like "copying/pasting the app onto your HD.Customizing Adium
Adium is incredibly customizable.
Open the preferences window via Command-, (thats the shortcut for the preference window for almost all apps)
Adium > Preferences > Appearance > Contact List > List Layout > Customize
Alternatively, check out http://www.adiumxtras.com/
for a bunch of customization options.The Dock
The dock is similar to the quicklaunch bar in Windows.
Applications in the dock are not the actual application, they're just shortcuts.
I drag all my favorite apps onto the Dock.
Alternatively, you can drag items you don't use often out of the dock (complete with a nice "poof" animation)Finder
The white pill button on the top right of the Finder window changes the window to a minimalistic mode.
The items on the bottom left side are shortcuts as well (so you can drag things in and out of it).
By default, theres already a Home, Desktop, Documents, Music, Applications, etc... shortcut
The actual files are located in that harddrive folder on the top left.
Harddrive > Users > your home folder > (this is where all the
Desktop/Documents/Music/Application/etc.. folders are located)
System Preferences > Place Scroll Arrows: At top and bottom (Windows style)
I can't stand having the top/bottom arrows next to each other.
System Preferences > Dashboard & Expose > Active screen corners (Expose shortcuts. You may hate it, you may love it.)
Mess around with the System Preferences! I love how all the system preferences are in one easy-to-find location. I always got lost when messing with system preferences on a Windows machine.
Once you're settled in and comfortable, I'll introduce you to Quicksilver, the ULTIMATE power users app.