SharePoint 2010 - Get Logged In User Details

To get the user details using JavaScript from SharePoint 2010, use the following code:

the SP.JS file should be available from the standard installation folder of SharePoint 2010

Sharepoint 2007 Access User Profile

To access user profile details from a page within SharePoint, you need the following:

Download the latest jQuery SPServices JavaScript from here
Upload the JavaScript to your SharePoint site
Add a Content Editor Web Part to the page
Edit the Content Editor Web Part, include the following:

The userName and Email have got the value of the logged on user