example explains you how to create lead record from Lightning component.

• Lead Record using Lightning Component

here we did the following things

• one apex class with aura enabled methods  which has lead insert.
• one  Lightning component you can see previous example how to create a component
• included lightning styles from lightning design system.
• include controller with lightning component to invoke apex method and process
• created one app to execute component

Apex class:

public class LightningLeadCreatecls {

   @auraenabled

    public static Id creatLeadRecord(Lead leadObj){

        upsert leadObj;

        return leadObj.id;

    }

}

Component:leadCreation

<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId" access="global" controller="LightningLeadCreatecls">
 <!--including lightning styles-->
    <ltng:require styles="{!$Resource.Lightning_slds+'/assets/styles/salesforce-lightning-design-system.css'}"/>
     <ltng:require styles="{!$Resource.Lightning_slds+'/assets/styles/salesforce-lightning-design-system.min.css'}"/>
<!-- Preparation of lead object with fields-->
    <aura:attribute name="leadObj" type="Lead"  default="{'sobjectType':'lead',
                                                           'FirstName':'',
                                                            'LastName':'',
                                                          'Company':'',
                                                        'Email':''}"/> 
   <div class="slds">
       <div class="slds-form-element">
          <label class="slds-form-element__label" for="FirstName">First Name</label>
          <div class="slds-form-element__control">
            <ui:inputText aura:id="FirstName" class="slds-input" value="{!v.leadObj.FirstName}" placeholder="First Name" />
          </div>
        </div>
       <div class="slds-form-element">
          <label class="slds-form-element__label" for="LastName">Last Name</label>
          <div class="slds-form-element__control">
            <ui:inputText aura:id="LastName" class="slds-input" value="{!v.leadObj.LastName}" placeholder="Last Name" />
          </div>
        </div>
       <div class="slds-form-element">
          <label class="slds-form-element__label" for="Company">Company</label>
          <div class="slds-form-element__control">
            <ui:inputText aura:id="Company" class="slds-input" value="{!v.leadObj.Company}" placeholder="Company" />
          </div>
        </div>
       <div class="slds-form-element">
          <label class="slds-form-element__label" for="Email">Email</label>
          <div class="slds-form-element__control">
            <ui:inputText aura:id="Email" class="slds-input" value="{!v.leadObj.Email}" placeholder="Email" />
          </div>
        </div>
       <div class="slds-form-element">      
          <div class="slds-form-element__control">
            <ui:button label="Save" press="{!c.save}"/>
          </div>
        </div>
</div>
</aura:component>

Controller:
-----------
({
save : function(component, event, helper) {    
    var action = component.get("c.creatLeadRecord");
            action.setParams({"leadObj":component.get("v.leadObj")});
            action.setCallback(this,function(result){
            component.set("v.isShow",false);
            var leadId = result.getReturnValue();
            alert('leadId'+leadId);
        });
         $A.enqueueAction(action);
}
})

App:
------
<aura:application >
    <c:LeadCreation />
</aura:application>


output:
--------