Question About Transparency in Flash MX

I have just recently gotten the program, and am trying to test my wings, and learn how to use it.

The ‘project’ I’m doing to test my wings is to use sprites of a cartoon character, and add it to a movng background. My problem is that I cannot get rid of the white background around the character and make it transparent.

I have been copyingthe sprites from another program and pasting them into Flash. Even making the background trans in the other program does not work…

If I’ve made ANY sense at all, could someone please help me out? It would be greatly appreciated.