With autofs you can easily mount network volumes upon first access to the folder where you want to mount the volume. Autofs is available for many OS and is preinstalled on Mac OS X so I show you how I mounted my iTunes library folder using this method.
autofs needs to be configured so that it knows where to gets its configuration. Edit the file /etc/auto_master and add the last line:
#
# Automounter master map
#
+auto_master # Use directory service