And if so, is there a way I could go Jimi Hendrix style and do bass guitar and vocals at the same time?

Hasn't this already been asked? Either way, you can't use it to sing though I do think there should be some option for it so people can sing and play an instrument at the same time.

I tried it the other day, it seems it was recognizing my voice as a mic, but it said the controller was disconnected, I think it must have been that I had my guitar on slot 1 at the same time.

I tried it, and it didn't work. Did it work for you?

Yeah, dude, why the heck can't we use it for singing? That would have been an easy way to save like $30. I guess it would interfere with voice chat while playing online so they didn't do it, but c'mon. It should have been an option.