Noteflight® is an online application that
lets you display, edit, print and play back music notation with
professional quality, right in your web browser. You can work on
a musical score from any computer on the Internet, share it with
other users, and embed it in your own pages. And it's
free for individual use.
Use the Draw Here bookmarklet to draw on top of web pages while you are browsing the web.
If you save your drawings, other Draw Here users will then be able to see your drawings when
they go to
the same page.