After following the tutorial here I ran into a problem. Here is what I did.

On my server I installed nfs-kernel-server and edited the /etc/exports file to include the folder I want to share:

 /var *(rw,sync)

On my client machine I edited my fstab file to include share:

 //128.251.xxx.xxx/var/ ~/uslonsweb003 nfs #username=[username],password=[password], 0 0

Entered command:

  sudo mount -a 

which gives this error:

  mount.nfs: remote share not in 'host:dir' format

Where did I go wrong with this setup?

Also if there is a better way (using command line) to setup a folder share on an Ubuntu 10.10 server that will be accessed by other linux and windows machines please let me know.

UPDATE:
The mapped drive is now not letting me create,edit,delete files or folders (readonly access) my configuration is as follows:

client fstab file:

 128.251.xxx.xxx:/var /home/coreyf/uslonsweb003 nfs rw,hard,intr, 0 0

server exports file:

 /var *(rw,no_root_squash,sync,no_subtree_check)

UPDATE 2:

Using Allans solution my drive mounted correctly however after putting rw,intr as my additional parameters I cannot create, edit and delete folders/files.