This feature is some of the very much awaited features amongst all new features in SharePoint 2010. People like to edit the item without opening that item in window. Just like ASP.NET grid provides the way of edit and then update by clicking edit button and then updating the record. 

Well, now this was possible in MOSS 2007 as well, but it required little trick, but with SharePoint 2010, it is easy to do that.

Just go to the view settings of any list and then enable the in line editing option.

Check in line editing option and save.

Now move back to list and move mouse cursor near the list item, you will see an “edit” icon against each list item

When u click on the icon, the selected row will be edited and 2 more icons, save and cancel will be displayed.

Make your changes and save. That’s it.