There are two types of "batch processing" that might match your question:
1 - Bulk import of products in a csv file. Main points that you might no read in the doc:
-- first export, so that you have a file format example
-- test your import on 10 products before importing your whole catalog
-- main caveats in the imported data:
== images file-names must start with / and are relative to /media/import
== product id are mandatory (as well as some other when creating products)
== when importing, change the default "bucket" size for products import from "1" to a value between "10" and "50" (the larger the faster.... but the more RAM is then needed and that might crash your server)
== you might need to adjust manually some setups, eg categories etc; use mass update, eg the one with extended grid-list from TBT
2 - Cron processing for such jobs as re-indexing etc. You may run your own "magento apps" by using Mage::app('website') instead of Mage::run('website') (see the /cron.php file)
