Question : Best software to provide remote assistance

I am the resident "IT Guy" for a small company. We have a small saleforce (about 10 people) who have latops which they take on the road with them. I'm looking for opinions on the best approch to be able to offer them remote assitance. I would like to be able to connect to their machines and see the desktop and take over control of the mouse/keyboard. Price is an issue as we are a small company with a limited IT budget. I have used RealVNC with some success... the problem lies with port forwarding and many times the salemen either can not follow my direction to forward the ports on their firewall/router at home, or they are in a hotel or other place where they do not have access to the routing device.
     What would the most feesable solution be that would only require that they have an internet connection? I've heard about GoToMyPC, and I'm thinking of looking into that, but if there are any free or one time charge software programs I would prefer that. All laptops are running Windows XP Pro SP3 and are typically connected to the internet wirelessly.

Answer : Best software to provide remote assistance

UltraVNC Single click works well, it just requires you to open a port at your end (not at the salesmans end) Its totally free. The interface is a little clunky, but once launched it works fine, giving you full control over their PC.

Team Viewer is another good alternative, but for commercial purposes it requires licencing.

Abode ConnectNow is a flash based screensharing system that also works quite well, although it seems less tolerant of low bandwidth connection in my experience.

Rob