I have been learning violin for about 2 years now, on and off, and I can reasonably play some basic stuff from sheet music.
Sometimes though, for more complex pieces, it is tricky to get a feel for how the notes match up to the actual expected way the song can should sound.
I have been using SoundSlice.com
It which allows you to import music from a pdf or use their excellent sheet music editing system to hand write out the sheet music if the importer isn't able to take in the music automatically.
The editor is the best I have seen anywhere, and would be cool if DAW's would have the ability to use something like it, especially the way it handles using the keyboard to quickly enter and adjust notes.
But, where this really shines and provides great help to the musician is that you can play the sheet music, sync it to a youtube video, and adjust the playback speed to even the slowest speed for when you are just learning the piece.
Also, as with how I started this whole thing, when you play the piece, and hear it as you expected it, and see that synced up with the highlighting of the notes on the sheet music, you get a more solid feel for what you are really trying to play.
Really, it is just a joy to use, and big props to Adrian Holovaty, who also apparently cocreated django, and his team for creating this awesome product.