what is actually local printer and network printer? what is the difference between them ? and what are the advantages of sharing printer? i really have no idea about it. help me please.

A local printer is plugged directly in to your PC (usually USB, LPT) while a network printer is available over TCP/IP. You can share local printers, buy a print server and have a true network printer if the unit doesn't come with a NIC, or the newer and more expensive printers have an integrated printerserver.

The difference is accessibility. It is easier to share a printer on the network with a printserver. If you share a printer off of a machine -- then when the machine reboots the printer is unavailable.