Open Flash:

1- select oval tool:
2- make an oval
3- Now on the above time line there are key frames when you make an oval key frame no 1 is inserted, now go to frame 10, right click -> insert key frame
4- From here make another oval , size of it should be maximum that you want. for e,g if u want that a small circle grows bigger, this size should be that maximum , hope get my point
5- last step right click on the last key frame that you inserted click create tween motion, also do the same for the 1st key frame.
6- preview your movie by pressing ctrl+enter.
7- export movie swf file

that's it in flash now through voda insert that movie by clicking Flash plugin

Congrat's