About "Search" option on your Site,local as well as on search engine

[vaibhav punekar]

Hello,
I am developing site for our office in which ZI have one search option.I do not know the exact way of achieving this task.I wish to perform do a search through my pages only.There are some ways that i know like putting some keywords in header Content="keywords" in your HTML tag.Can anybody can throw some light on it?Also if I wish to write a search engine how do I go about it?Or do we just need to register to existing search engines like "Google" etc.In such case how can I make my link to be the first one to appear in the search results after somebody enters some keywords in "Google search" which are relevant to my site?
Thank you in advance.