Hi roger,
You can change the preference of the dns servers on your lan card properties. there will be a field giving the primary dns & alternate dns servers. you can put ur vpn dns server first and then the internet server.
You will run into serious problems if you do this. when u try to browse, all ur internet URL request will go to the vpn dns server first and then to the internet dns server. this will cause a lot of unnecessary traffic on ur VPN tunnel.
the best way to go about this is to add host entries for the servers u are going to access through the vpn tunnel on your PC. why dont u try this ?
all the best.. rate replies if found useful..
Raj