And, ee3, yeah, you've probably only watched the dvds, which would be why you've only heard the Jango voice. Here's a link to where you can hear Boba's original voice. http://www.youtube.com/watch?v=a897FGgDJy8 Isn't it lovely?

EE3, this is how the releases go:
Theatrical editions came out on vhs first.
Then in 1997 they made a special edition that cleaned stuff up and changed a few things, Boba's voice was not among the changes yet. These are the special edition vhs's.
In... 2005 I think it was? They released the OT on dvd for the first time, it was in these that Boba's voice was changed. They also messed up quite a few other things but that's besides the point right now.
Then the original theatricals on dvd, I believe is what those are, that I posted of up there.

That's not counting the numerous repackagings. Speaking of which a new boxed set is due out next month, yay!

The only other thing I can think of is this: You know those things you can buy that you can use to transfer vhs onto dvd? Well, use your vhs ESB and transfer it to dvd. If I had one of them I'd do that.