RSS widget cache

Is there a way to remove or decrease the cache time for the rss widget? I’m using it as a latest forum posts widget, but I’ve read the update for the widget to display new posts is once every hour.

Found a post just after I posted this.

add_filter( 'wp_feed_cache_transient_lifetime', create_function( '$a', 'return 1800;' ) );

Adding this to functions seemed to work, adjusting 1800 to whatever you need.