How to implement theme shortcodes in text outside of pages?

You can run the text through do_shortcode:

echo do_shortcode( $your_text_with_shortcodes );

or you can apply the_content filters to the text, which does the same thing as above along with some additional formatting goodies, like auto paragraphs and texturize:

echo apply_filters('the_content', $your_text_with_shortcodes);