I needed to use my company pre-designed Microsoft Word document format (fill in the blank style). I edited the document with OpenOffice.org 2.2 under Ubuntu. I found no problem at all. When I was asked to save as Microsoft Word or Open Document format, I chose Microsoft Word format.
Later, my boss told me that she could edit the document any further under Microsoft Word 2000. Although all the data and format are same as I edited, the document cannot be edited anymore.
In conclusion, OpenOffice.org 2.2 is not fully compatible with Microsoft Word 2000.