Apex Coding on Sending Email................

Controller:
----------
public class SendEmailSample
{
    public String emailTo {get; set;}
    public String emailBody {get; set;}
    public String response {get; set;}
    String[] Users = new String[]{};
    //string Users = null;
 
    public string[] getUsers()
    {
      Return Users;
    }
 
    public void setUsers(string[] Users)
    {
     this.Users=Users;  
    }

 public List<SelectOption> getItems()    
    {
        List<SelectOption> options = new List<SelectOption>();  
        List<User> UserVar = [Select u.Email, u.Name from User u];            
        for(User U : UserVar)      
        {            
          options.add(new SelectOption(U.Email,U.Name ));    
        }        
        return options;        
    }
     
    public PageReference sendEmail(){
        Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
        mail.setToAddresses(Users);
        mail.setReplyTo('arjunan@yahoo.com');
        mail.setSenderDisplayName('Thylak SOFT');
        mail.setSubject('Test Email From Force.com Sites');
        mail.setPlainTextBody(emailBody);
        try{
            Messaging.SendEmailResult[] resultMail = Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
            if(resultMail[0].isSuccess())
                return Page.opptyStep2;
                //response = 'ok sent!';
            else{
                response = resultMail[0].getErrors().get(0).getMessage();
            }
        }catch(System.EmailException ex){
            response = ex.getMessage();
        }  
        return null;
    }
   
    public PageReference test()
    {
      return null;
    }
}



Page Editor:
------------
<APEX:PAGE controller="SendEmailSample"  sidebar="true"  standardStylesheets="true" showHeader="true"  >
    <APEX:FORM >
        <APEX:PANELGRID columns="2" border="0" cellspacing="2">
            <APEX:OUTPUTTEXT value="Email To :"></APEX:OUTPUTTEXT>
            <apex:selectList size="5" multiselect="true" value="{!Users}" style="width:400px">
            <apex:selectOptions value="{!items}" ></apex:selectOptions>
            </apex:selectList>
            <APEX:OUTPUTTEXT value="Email Body :"></APEX:OUTPUTTEXT>
            <APEX:INPUTTEXTAREA style="WIDTH: 400px; HEIGHT: 100px" value="{!emailBody}"></APEX:INPUTTEXTAREA>
            <APEX:COMMANDBUTTON value="Send" rerender="statusMail" action="{!sendEmail}"></APEX:COMMANDBUTTON>                  
            <APEX:OUTPUTPANEL id="statusMail" layout="block">
                <STRONG><APEX:OUTPUTTEXT value="{!response}"></APEX:OUTPUTTEXT></STRONG>
            </APEX:OUTPUTPANEL>
        </APEX:PANELGRID>
    </APEX:FORM>
    <apex:outputPanel id="out">
<apex:actionstatus id="status" startText="Loading...">
<apex:facet name="stop">
<apex:outputPanel >
<!--<p>You have selected:</p>-->
<apex:dataList value="{!Users}" var="c">a:{!c}</apex:dataList>
</apex:outputPanel>
</apex:facet>
</apex:actionstatus>
</apex:outputPanel>
</APEX:PAGE>