I am wondering if there are any good voice manipulation/synthesis software for Fedora (I'm willing to use Windows if necessary, but I'd prefer Linux)

I want to be able to do something like this:

There is an mp3 file which is a recording of me talking...The program reads the mp3 file, and then acts as a text-to-speech converter using the voice it reads from the music file.

I know there are a few text-to-speech converters out there, but I want it to imitate my voice using a recorded sound file of me talking. If that's infeasible for whatever reason, I'm open to other suggestions on how this could be achieved.

You can use espeak or festival for this sort of thing. As far as trying to imitate your own voice, you will have to tweak the settings to get it as close as possible. You would have to pretty much reprogram which ever one from the source code if you want it closer to your voice, as both programs don't have the capability to exactly change how it sounds.