I like to access my Mac from work (Linux) and I wonder if it is possible without installing additional software like TeamViewer or ChickenVNC. I also noticed somewhere that it is possible to wake my Mac via WiFi. What is needed for that (Mac has to be plugged in? Do I have to be in the same Network?) and how do I do it?
Part 1 - VNC
This is pretty simple, you'll need to go to System Preferences -> Screen Sharing and then click on Computer Settings. From there you can select VNC Viewers may control this screen with password and supply a password
Part 2 - WiFi Wakeup
Still in System Preferences go to Energy Saver. You can only do this with the Mac running on power (if its a portable), but you should see an option to tick called Wake for Wi-Fi Network Access.
10.8.2 Problem - if you're running the latest public release of Mountain Lion you may find this doesn't work (detailed here -> https://discussions.apple.com/thread/4160837) however if you have access to a developer account, 10.8.3 reports to fix this. I can confirm this works under 10.8.3 on a MBPr 2012 model.