PHP script for prommatically import product from XML feeds to MAGENTO online store

Magento 1.8.0.0 online computer store is created at [login to view URL] Depends on current product categories a custom PHP script must be created which insert products, both with images from 6 custom XML feeds. The script must be independent from the magento admin panel. It must be available to call alone from web browser and/or cron job. XML scripts are available online and must be accesed online with cron job. Note that there are 6 custom XML formats, from diferent suppliers with diferent categories, so the script must be cusomizable from a PHP config file. Images must be stored on a local server from the remote url address given and an option with watermark must be available. Before insertation a check if product exists must be made in order to do not insert one product more than once. If product exists the price update must be made, but do not affect text fileds and parameters which can be changed from Magento admin after insertation. The PHP script must insert the products auto incrementing the IDs with no conflict to other products inserted from the Magento Admin Module. Here is a sample of first 4 RSS feeds Please note 1 and 2 contains very huge files, with all articles. 3 and 4 has 3 steps access from categories po product info from a well formated diferent rss feeds.