Hello. Can Domino change an uploaded attachment (such as a MS Word or Excel doc) to HTML? Can LotusScript do it?
LotusScript can't do it without assistance because the Domino server doesn't know how to interpret the contents of MS Office files. However, if your Domino server is running on an MS Windows box with MS Office installed, you could use LotusScript to detach the file to the local file system, then use OLE automation to read the file and save it as HTML, then attach or embed the resulting HTML in the Notes document.
That's more code than I have time to write now, especially considering that the HTML export files might contain images which are saved in separate files, which would also have to be attached to your Notes document. However, watch for an LDD Sandbox download, which should be available within a week or two.
Note: As of this writing, Domino 6 LotusScript doesn't let you get at attachments created from a browser -- it seems the NotesDocument.EmbeddedObjects property is broken. Development is working on it.