Brainslayer is working hard to merge the code base of DD-WRT with the OpenWRT firmware. This means that, for the most part, OpenWRT's package management system, ipkg, is available for DD-WRT. This allows for an easy way to add features not already in the DD-WRT firmware. Since ipkg is a command line program, you will need to either Telnet or SSH into your router to run this utility. You also need