umen 0 Newbie Poster

Hello all
i need to be able to modify Microsoft office existing file like or rtf files
adding text and misc options to the document and then saving it
i don't what to be restricted to windows because most likely the process will be running on Linux .
what is the best way to process such task . i was thinking to use open office API , or maybe
working on rdf level and then convert it to doc file .
some one have ideas?
Thanks allot