ViArt has Article RSS feeds built in.
For articles go to " Administration > Articles > (Your Category) > Edit Category" and activate the RSS feed. The RSS icon will appear where you select it to be. You can also select an external RSS feed to appear on your site.
Ive also done an thread on creating RSS in blocks
http://www.viart.com/how_to_create_rss_feed_custom_blocks.html