sudo mount -t nfs -o rw server:/var/www /webserver
or
mount server:/var/www /webserver
The mount can be put into /etc/fstab, e.g.:
server:/var/www /webserver nfs rsize=8192,wsize=8192,timeo=14,intr,user
This doesn't mount the nfs export automatically during startup, but any user can mount it by executing "mount /webserver". Be aware that if you have mounted another filesystem under /var/www (e.g. if you keep all html data on a seperate partition like /var/www/htdocs), these won't be available unless you export the partition's mountpoint seperately!