Flash is a software that is used for 2-D animations. This software can also be used for creating websites. Flash contents can be used on webpage. Animations can be easily viewed in any browsers if it's plugins are installed. Usually buttons are made using flash. Not only buttons but the whole site can also be designed by this software.
The thing you should learn is how to animate in Flash. If you don't know animating or using Flash at all then no problem. Now soon the Flash tutorial is going to be included in this site. Till then wait for the tutorial to come.
Click Here to see my website completely made with Flash.