iGoogle is the personal version of Google , customized for your need. You need to Sign In google.com to land on your personal iGoogle page. Google offers various tools & gadgets to use this page as one single dashboard.
The Google developer community have built small but wonderful tools to look up your emails (like Hotmain, Gmail, Yahoo! Mail etc), look up weather, or wikipedia, or a map & driving directions.
You can even launch applications like Google Talk from the iGoogle page.