What is actually an IC (Integrated Circuit)?
It's funny that you have a picture of one in your profile pic. :)



The arrow points to the most obvious integrated circuit or chip in you pic, there is another square one to the left of the TX and RX markings.  There are lots of different types of ICs -- most are black and come in different shapes and sizes, different number of legs, but most have some form of writing on the back that Google can use to locate the data sheet, or general help.  Have a quick look on Wikipedia for a more authoritative description.