Remote access to PowerPC Leopard Server
Try PortMap -- it's free, universal binary (PPC and Intel), and supports a variety of routers.  Just have it map ports 22 (SSH) and 5900 (VNC).  Note: I'd recommend  using nonstandard public ports, to cut down on the number of password-guessing scans you'll get, and also making sure you don't have any accounts with easy-to-guess passwords (because you'll still get a few scans, no matter how creative you are with port numbers).