I've wanted to be able to label my maps for a while without a lot of trouble, so this application at:
http://bike.zgroks.com/index.html allows the user to post "dynamic labels" to the map. User right clicks on map then selects size of label and types in text. Shows up as a label that's a marker, with an associated infoWindow, user can upload photos and post permalinks to facebook from the 'label'. Tried to do with javascript sprites but with PHP it's much easier. In addition to making labels that act as markers, also works for creating iconic labels for the map. I'm using this map to track proposed changes to a bicycle map that I am updating. Cheers.