Develop script for uploading ind including posts into WordPress MySQL database

I have set up a new WordPress-based site into which I want to upload posts. I can create any sort of table/file (such as tab-separated files). I want to upload such tables RAR-compressed since my internet connection is usually poor and one (compressed) upload will contain several MB of data. The uploaded files (ca. 20,000 posts/day) have to include the following: - Title - Content - Category - Tags - Meta Keywords (?) Any other data could/should be created by the "upload script" to be developed.