airtunes as router help

[nichos]

Hi all, I'm looking at getting an airtunes airport router (I've given up on a video one:)). Here's my setup. I already have a wireless router, I know I can connect wireless to that router with the airtunes, but my question is, can I use the ethernet port on the airtunes to plug a computer in? Or, is this port only for an incoming connection?

thanks in advance!