Folks, here's what I do:
Install PalmVnc on your Treo and on each computer on your home network that you wish to control remotely.
Go to
www.no-ip.com and create an account for free. You will assign it a unique username that will form part of the url for your home network. For instance you could reach your home network by typing "http://username.myvnc.com".
Next, download no-ip's Dynamic Update Client (DUC) software from their site and install it on one of the PCs on your home network. This app will get your real IP address and report it to the no-ip servers at a given interval. I have mine set up to update every 5 minutes.
Go to your Linksys' Forwarding setup page (in the "Advanced" section) and click on the UPnP Forwarding button. Make a new entry on this page for each computer you wish to remote control as follows:
For "Ext. Port" choose a port number for each PC starting with 5900 for the first PC (5901 for the next PC, etc.).
For "Protocol" choose TCP. For "Int. Port" type in 5900. "For the IP Address" enter the last digits of the IP for that PC. Make sure to click the Enable check box.
Do this for each PC then click the Apply button.
On the Treo VNC application create a profile for each PC in your home network. For the Address enter the URL you created at No-IP along with the proper port number for that PC. For example: username.myvnc.com:5901
It really sounds a lot more complicated than it is. I use this setup and am able to reach any computer in my house from my Treo from anywhere I am as long as I've got a signal.
The only drawback has always been that the screen resolution on the T600 is so low that you can only see a small portion of the screen at once. This means that you must scroll around all the time. You can choose a different scale factor for the Treo display in the VNC app, but the more of your PC you show, the smaller the text gets and with the T600 resolution, it becomes illegible. This is the main reason I will be getting the T650; I will finally be able to see more of the screen at once on my Treo and still be able to read it.
Note: I have noticed that some of the newer Lynksys routers (like the WiFi G-routers) do not have the ability to do UPnP Port Forwarding (just the regular Forwarding) so you may not be able to control more than one home PC.