Is there a recording App out there for Musicians where you can load in a song from a CD ... remove vocals and say guitar, and then play or record voice and instrument to the music??
I noticed some people were saying you can't do what you are asking for. Well I'm here to tell you how. There are many many apps that can do what you want. The best one which lets you edit anything on a track of a cd once you have ripped it into the right format is called VocaLive. For example, I just put a song I love singing into my itunes library. I opened VocaLive and went to import song. Once the song is imported, you simply click the NO VOICE button and it will put the song, without the vocals in to one of the four tracks available to you. (The other three tracks can be used to add your own instrument or you can sing four different parts if you want!) Also VocaLive allows you to edit your voice with many different sound effects, as well as edit the music track. It's not always 100% removal of the vocals because most recording studios mix the vocals and instruments into one main track. I then record myself singing and viola! All done! VocaLive had a trial last time I checked. There is also PocketKaraoke but it doesn't have nearly as many features as VocaLive.
VocaLive is like a mini recording studio. It can be a challenge to figure out how to use it if you have never been in a studio before but once you get the hang of it, you will be the new start of the show! If you need help using it, by all means send me an email.
Good luck and rock on Rockstar!