Yes, these are the actual voice actors singing. I saw something like this, except it was with Naruto. Since a lot of the voice actors for Bleach and Naruto are the same, (Itachi is Ukitake...WTF?) I decided to make my own.
I randomly put together clips from episodes that were already on my computer, so please excuse the lameness of it. There will be a second one, so if your favorite character wasn't featured, I'll put them in the next time. Don't forget to vote!