It probably best to save documents as an ODT file, and than save it as a .doc file by doing a Save as since there may be some benifits keeping files as ODT files, and doing a Save As to save as a .Doc file for others.
The main benifit is it is an Open Source file format instead of a proprietary document format which is closed source like .doc.
IBM Lotus Symphony Office Suite at
http://www-03.ibm.com/software/lotus/sy ... f/products is also free, and uses the ODT standard.
Lotus has a slightly nicer user interface, and has tabs like web browsers for easily working on multiple documents at the same time. I think it also has a built-in web browser in it the last time I used it a few years ago.