There are people who do this. Do a search for "music transcription services".
Don't be too sure that you can't do a lot of this yourself, though. If you know the melody notes and are familiar with the style you can usually come up with a pretty good facsimile. Most popular music follows certain conventions, so you know that a ii chord will usually lead to a V, etc. Listen for the bass line and build on that. You may not end up with the exact
harmony the composer used but people revise chord structure all the time. As the Duke said, "If it sounds
good, it is