An easy place to go for creating quick 2-D, frame-by-frame animation is www.aniboom.com . Sign up if you want to, and if you don't, and just want to start creating animation you can be a guest and get right on going. A couple things you should know before going there is that the shapes you can use is limited to: rectangles, circles, triangles, and half circles, You are NOT able to draw shapes! You can increase, or decrease their size, and also rotate them. once you create another frame the shpaes and colors will be the same as the frame before it (untill you change it), this means that each time you create a frame you dont have to create the shapes sizes and colors all over again.
If you want to check out on of my videos click here>http://www.aniboom.com/shapeshifter/354873/stickman-new-2/