Casting Call-Harry Potter and the Force

Hello, I am new to the whole Fan Audio genre, but I am trying it out for a shot. I am doing mainly a test audio parody, entitled Harry Potter and the Force, in which Harry Potter is fighting Lord Voldemort untill he Runs into Luke Skywalker. Voldemort escapes and Luke Tells Harry to learn the ways of the Force. it is intended to be a series, but I don't think it will be popular enough to continue it, but I am looking for voice actors who can play the parts I will describe in a moment.

First of all, I am still learning how to make Audio Dramas/Parodies, so any help will be apreciated, for example, do I just have the actors send me their lines and I put them together or do we all get on something like skype and record the lines, similar to shooting a movie?

Ok, Here are the parts I need:

Harry Potter:
It doesnt need to be an exact Dan Radcliffe(sp?) ripoff, but basically a person who is between 15 and 17, or someone who can easily impersonate someone of that age. Not too hard to pull off.

Lord Voldemort:
A man with a snake-like voice, and a somewhat high pitched one. anyone who can basically pull of a sinister and evil voice should have this down.

Luke Skywalker: I am sure you all have seen Star Wars , so someone who can do a decent Luke Skywalker voice will work

Darth Vader: Someone who can pull of a decent Vader voice with me having to do as little editing as possible

Albus Dumbledore: Someone who can pull of a calm old man pretty much...

That's it, this is a fairly short project, mainly to see if I can do a decent audio parody/drama. I could probably pull off all of these voices myself, but I want to get the feel of casting voice actors should I continue this series or something else.

Once again, help would be appreciated, and If you would like to see the script, go ahead and PM me or just tell me here that you would like to see it.

and also, like I said before, this is mainly a test, so don't hurt me too ad if it turns out I don't know what I am doing...
Thanks,
Aroman

EDIT: I also need a narrator, not much to say, just a deep voice that doesn't stutter too much, he only gets one line though, and I stutter too much so I cant be it