Currently I am personalizing my Ubuntu installation and i want to write a small applet to add it in the top left corner of the screen. This should be a "main menu" like in Mac OS X where i have a menu that opens when i click the (Apple/"Tux") logo and offers me to run the updater, the software center, etc. With this i could combine this applet with my global menu i already have activated to achieve a mac-like menu interface. :-)
Which tools and programming languages are used to write such applets and what is the first place i should look for such information?