Google Webmaster Tools is a tool and the media used google for two-way communication between the google and we webmaster.Dengan as Google Webmaster Tools, we can optimize the indexing process. use of Google Webmaster Tools Web Page Making Being Search Engine Friendly.

1.Google Sitemap sitemap is a list that contains the url of our website functions to facilitate the entry to boot google and mengcrawl page, the page we have provided the url to.
2.Robot.txt
Robots.txt is a file that contains restrict / regulations that go in to the bot / crawler not to mengindek website or a page or even the whole directory structure of the website, depending restrict it, in Google Webmaster Tools also have its robot validator.
3.Link
Link on the menu can see the list of inbound links, internal page, and you can also see how many pages you have in the index by Google.
4.Domain Preference
Preference domain prefix is the selection of the domain if you use the "www" or "without www"

go to google webmaster tools:
http://www.google.com/webmasters/
or
http://www.google.com/webmasters/tools/

but you must first have an account, at least you have a google email.

utilize radio waves and/or microwaves to maintain communication channels between computers. Wireless networking is a more modern alternative to wired networking that relies on copper and/or fiber optic cabling between network devices.

A wireless network offers advantages and disadvantages compared to a wired network. Advantages of wireless include mobility and elimination of unsightly cables. Disadvantages of wireless include the potential for radio interference due to weather, other wireless devices, or obstructions like walls.

source:

Bradley Mitchell, About.com