you can use the feedburner rss script (google it) to add it only to the mobile version of the forum or both the mobile and pc .
But if what you are talking about is only the recent post you can add it via admin-> configuration -> current theme -> number of recent post to display -> enter the desired amount of post and install the wap mod to automatically show it along with your wap version.
Number three option is for you to add a link in the footer. something like myforumurl.com/recent