OK, you probably know this from SharePoint 2007 and is not a big news for you, but this is just more a reminder for myself. I am always forgetting the URL to this :)

The User Information List stores information about a user by having some metadata set up for the user (Ex: Picture, Email, DisplayName, LoginName etc. ). When an user is granted access to a site, a new item will be created in this list storing some information about the user.

The User Information List can be accessed via the browser by navigating to /_catalogs/users/simple.aspx from your site or /_catalogs/users/detail.aspx.

This works for both versions of SharePoint 2007 and SharePoint 2010.

If you want to write some code using this list you can do it like this:

// Instantiates the User Information List
SPList userInformationList = SPContext.Current.Web.SiteUserInfoList;

// The actual User Information is within this SPListItem
SPListItem userItem = userInformationList.Items.GetItemById(SPContext.Current.Web.CurrentUser.Id);