Bikely.com is my favorite site for mapping and sharing bicycle routes. They have a very intuitive UI for drawing on Google maps and letting you annotate the waypoints to make descriptive cue sheets. But… They’ve been down more than up recently. The word on the street is that they’re going through a major upgrade to get better scalability and features, and predict a relaunch in a week or so. I sure hope they finish soon!
http://www.bikeradar.com/COMMUTING/forum/viewtopic.php?p=17105449#17105449
http://www.bikeradar.com/COMMUTING/forum/viewtopic.php?p=17105449#17105449
Have you tried google tracks? I used them up north dirt biking, but I didn’t try any annotations