There are a couple useful things you might want to add to the /etc/ppp/options file.
One is an idle time. Pppd can terminate the connection if it has been idle for too long. This could be nice if your isp charges by time, or if you don't want to keep your phone line tied up. To use this feature, simply add the line:
# Idle after X seconds idle X
Replace 'X' with the number of seconds you wish the connection to terminate after.
The next feature is "dial on demand". This means that every time you attempt to open an interent connection, pppd will try to open a PPP connection to your ISP. In order to do this, add the following lines to /etc/ppp/options
# dial on demand demand
This should make pppd dial out when necessary.