Help with remote connectivity

[Aesthetic]

basically i need the simplist way possible to allow both: A) me to access clients desktop computers (in multiple distant locations) to troubleshoot software, apply updates, and exchange files between their pc and a file server on my network; and B) allow them to remotely connect to our file server to upload/download data files. all file sizes would be no more than 50MB. This would all be in a Windows environment. 2003/2000 on the server side, XP Home and Professional on the client-side.

i know that VPN access combined with AD and security features is a fairly simple way to achieve B using 2003 server. what are advantages/disadvantages to using Windows VPN as opposed to, say, Cisco VPN Client or similar options?

What would be the best way to go about achieving A without forcing them to be a part of my network? All Client-side computers would be Running Windows XP Home or Professional and would already be part of a small, office based workgroup. Is it possible for the VPN server to initiate a session?

forgive me if this is a stupid question, and thanks in advance for your help.

Edited November 16, 2005 by Aesthetic

[Rob00GT]

Just to clarify, all computers are not on the same network? Are they two separate networks at different locations that require connectivity over the internet? Or is there a central "home" network and a bunch of individual clients dispersed all over the place that must be connected over the internet?

Edited November 16, 2005 by Rob00GT

[Aesthetic]

No, the computers are not all on the same network. The "home" network runs a mixed 2003/2000 server environment with local XP clients. The computers i need connectivity with are not a part of any network, rather their own small office workgroups. The client computers are not part of our company, they are customer computers in multiple non-server environments in varying locations. Hope that cleared things up a little better.