I find that even use Open Office and insert a picture in to a table, it sometimes moves.
What is your delivery mode for the newsletter?
This will determine the output format, although it is hard to imagine it'll be anything, but PDF, the only question is whether it is print-ready, or online distribution?
The latter will be perfectly served by OpenOffice built-in PDF engine, the former might require something a bit more sophisticated, if you have to deal with bleeds, crops, trims, layers, etc, etc ...
To prevent anything shifting in your newsletter, that is if you're simply sending it to your subscribers via email, or making it available through other online distribution means, just use OO own, excellent PDF creator: click File, then select this:
If, on the other hand, you're sending this to commercial printers, particularly for a 'proper' offset printing, then much will depend on their setup and requirements - let me know if that's the case, I'll be able to guide you through the process ;D