Yes, simply add feed/ to the end of each url and you're good to go.
http://mysite/index.php/tag/electro/feed/http://mysite/index.php/category/web+post/feed/Make sure you're in Advanced mode in PowerPress. In the Feed Settings page, make sure the first option is selected to enhance all feeds (including tags and categories).
The custom podcast feeds in PowerPress are separate from category or tag feeds. The custom podcast feeds allow you to associate different media to each feed, which is different than category or tag feeds. To create a custom podcast feed, go to the Custom Feeds section in PowerPress settings and click 'Add Custom Podcast Feed'. It should be self explanatory from there. Again, this is available in Advanced Mode.