UPnP is preferable or easiest; instructions can be found here Connection problems? Check here first! (click on link)

But manual port forwarding is generally more reliable. Instructions also in the link I gave you. Also http://linksys.custhelp.com/cgi-bin/...type=search_nl & static ip here http://linksys.custhelp.com/cgi-bin/...TVUxMA**&p_li=

but better here for port forwarding http://portforward.com/routers.htm