I don't know about HTML, but there's a OD->Markdown script out there: http://www.freewisdom.org/projects/python-markdown/odt2txt.php
Been there, tried that:
1) doesn't preserve URLs and has some other limits I don't remember now. May hack it, but:
2) the real problem, not to mention the only relevant on this list, is not how you arrive to HTML or markdown from whatever you started from. It's how to tell the darned Drupal "here is a new node" WITHOUT using a browser, that is entering text, taxonomy etc... from a shell or perl script.
I suppose it'd be possible to use a script like that to make an OpenDocument input filter for Drupal, which could take the content of the node from an attached OD file -- now *that* would be cool.
This has nothing to do with my original request. I do NOT want to directly upload .odt files in the drupal form, even if I agree it would be really useful. I do NOT want to use that form at all. I want to upload stuff to drupal with a script.
Ciao, O.