Those who still use Windows and Word, MagicScore, one of the decent closed-
source notation programs now has a plugin for editing and embedding score into
word documents. (What gets embedded in the doc are pictures--this is not
really full OLE/embedding so results can be opened in OpenOffice.)
http://www.musicnotationformsword.com/
You can get it for $49 for a short time if one dare spend money.
For the rest of us: OpenOffice and AbiWord have plugin APIs as well. Anyone,
mscore, nted, want to do something like this? Who knows? Linux folks might
even purchase such an add-on to their favorite GPL product!