New Post: GetUserProfileByName

 $().SPServices({
            operation: "GetListItems",
            async: false,
            listName: "User Information List",
            CAMLQuery: "<Query><Where><Eq><FieldRef Name='ID' /><Value Type='Counter'>1</Value></Eq></Where></Query>",
            CAMLViewFields: "<ViewFields><FieldRef Name='LoginName' /></ViewFields>",
            completefunc: function (xData, Status)  {
                alert(xData.responseText);
            }
 });