GeekTool is a preference pane module that lets you display 3 different types of information on your desktop:
Additionaly, you can set "always on top" windows to keep a constant eye on certain information, as your clicks always goes through to not disturb your habits
Users of the first version of GeekTool will be suprised to see all the new features. The reason I released only one version of GeekTool 1 was because I was focussed on a swift version 2.0 release. The preferences from version 1 are not compatible with version 2.0, you will have to define your entries one more time, sorry.
Copy "GeekTool.prefPane" in your users "Library/PreferencePanes/" or "/Library/PreferencePanes/" to globally install it (available for all users on the system).
To uninstall, please see "Uninstalling" section for special instructions.
Once installed, GeekTool is available in System Preferences in the "others" section. You do not need to restart, or log off in order to begin using GeekTool.

First of all, click the "New log" button, a default one will be created and named "Console".
Now, you have to choose the type of log you want to create :

You can type a path to your log file or click "Choose". to see a regular file selection panel.
Next, set up Background and text color, each can have an alpha value as you can see at the bottom of the color palette. Choose a pretty font and a text alignment.
If you want drop shadows under text, or under full windows, use the appropriate checkbox. Be careful, a window without a background cannot have a shadow. Uncheck "Shadow window" before changing the background color.

Type here the shell command for the output you wish to see, you can also adjust the refresh value. Don't set too short an interval or your machine's performence will drop dramatically.
Colors and font options are the same as "File" type.

Type URL (local file with file:// or remote with http://) and the refresh interval of the picture. As a test, you can take this webcam of the Eiffel tower. Cocorico.
Different types of frames are available, try them and choose one you prefer (the traditional "Bezeled" is very cool).
Choose your scaling between :
The first time GeekTool is started, it creates a default group that you can rename in the customization
panel.
Click on the groups menu on top of logs list and choose the "Customize group" item.
You will see a sheet appear with the list of groups currently present :

From here you can easily create new groups, delete a group or even duplicate, usefull if you wish to have two identical groups - one showing console log and another showing the system log and quickly switch between them.
Click twice on a row to rename a group.
Log grouping would not be so great without a way to quickly switch between those groups. That's why you can enable a menu item always available to list groups and switch GeekTool's state or open preferences :

You can reorder the menu by clicking with the Command key down and moving.
To uninstall GeekTool you absolutely need to use the "GeekTool Uninstaller"
program to make a clean uninstall.
Because Apple did not make public the menu API used for the GeekTool menu feature, there is a little hack called "MenuCracker" installed to show the menu, the uninstaller removes the hack and the preference pane. By the way, it does not remove the preferences, so you will have to do it manually if you really want to remove them. The file to trash is Library/Preferences/org.tynsoe.geektool.plist.
First of all, thanks to Véronika and her patience while I was spending long evenings and nights coding GeekTool.
Thanks to Christophe, for his intensive beta testing and great ideas.
Thanks also to Nicolas, for passive beta testing!
And thanks to Apple for making Cocoa so accesible and easy to learn.