Having VPN problems? A new set of appliances is beginning to attract mainstream attention: SSL VPN's. This class of device removes the need for any client-side software. On the client, only an SSL-capable browser is required.
External users (employees, business partners, etc.) authenticate through the browser and surf the intranet as if they were inside the firewall. Strong authentication (e.g., token-based, biometric, etc.) is supported, but weak auth (user-name and password) is an option as well. Windows file shares and other non-port 80, non-port 443 traffic can be supported, depending upon the vendor.
The leader in this space (and entrants seem to be popping up daily) is Neoteris, recently acquired by NetScreen for approximately $200 million. If you're looking to reduce VPN-related headaches, this class of appliance could ease your troubles considerably.