infared with my mac

I hace an iMac G5 that was built in 2005. It is the model that does not have the isight built in. It seems that some of these models have an IR and some do not. I would like to know if I have the option to install an IR port? Is this something that apple has to do or is this something that is installed on the motherboard? I want to use one of those IR remotes.

I am an apple novice.

I know of no way to retrofit a remote sensor onto a Mac that doesn't have one. Moreover, FrontRow isn't available except with a remote-equipped Mac. (There was a hack, but it involved a pirated version and it broke, sometimes causing serious problems, with later software updates.)