vpn and eth

[jack]

Interesting... As this is my first experience with a vpn client, I
noticed something different - when the vpn is connected, I cannot
send/receive mail nor can I connect to internet sites in my bookmarks.
I am assuming it is because ppp has taken control of the primary
ethernet interface in use.

If it were possible to set this up so that the vpn connection could share its traffic 
with normal web traffic, would this introduce vulnerabilities into the pipeline?
If not, can someone shed some light as to how to set this up?