Hi,
Wrapper Class:-
A wrapper or container class is a class, a data structure, or an abstract data type whose instances are collections of other objects. In Apex and Visualforce this type of class can be extremely useful but to a new developer the talk of wrapper classes may fly right over your head, it definitely did for me. Here I will supply a simple demo of how wrapper classes can be used.

In the Visualforce community boards one of the most commonly asked questions is, "How can I display a table of records with a check box and then process only the records that are selected?" This is a perfect scenario where a wrapper class can be used. Most of my instructions and comments are in the code but anyone should feel free to modify this entry to make it easier to understand.

Use of Wrapper Class:-
See these links
http://wiki.developerforce.com/page/Wrapper_Class

Ex:-

First the Controller:
public class wrapperClassController {

//Our collection of the class/wrapper objects cContact
public List<cContact> contactList {get; set;}

//This method uses a simple SOQL query to return a List of Contacts
public List<cContact> getContacts() {
if(contactList == null) {
contactList = new List<cContact>();
for(Contact c : [select Id, Name, Email, Phone from Contact limit 10]) {
// As each contact is processed we create a new cContact object and add it to the contactList
contactList.add(new cContact(c));
}
}
return contactList;
}

public PageReference processSelected() {

//We create a new list of Contacts that we be populated only with Contacts if they are selected
List<Contact> selectedContacts = new List<Contact>();

//We will cycle through our list of cContacts and will check to see if the selected property is set to true, if it is we add the Contact to the selectedContacts list
for(cContact cCon : getContacts()) {
if(cCon.selected == true) {
selectedContacts.add(cCon.con);
}
}

// Now we have our list of selected contacts and can perform any type of logic we want, sending emails, updating a field on the Contact, etc
System.debug('These are the selected Contacts...');
for(Contact con : selectedContacts) {
system.debug(con);
}
return null;
}

// This is our wrapper/container class. A container class is a class, a data structure, or an abstract data type whose instances are collections of other objects. In this example a wrapper class contains both the standard salesforce object Contact and a Boolean value
public class cContact {
public Contact con {get; set;}
public Boolean selected {get; set;}

//This is the contructor method. When we create a new cContact object we pass a Contact that is set to the con property. We also set the selected value to false
public cContact(Contact c) {
con = c;
selected = false;
}
}
}

And then the Page:

<apex:page controller="wrapperClassController">
<apex:form >
<apex:pageBlock >
<apex:pageBlockButtons >
<apex:commandButton value="Process Selected" action="{!processSelected}" rerender="table"/>
</apex:pageBlockButtons>
<!-- In our table we are displaying the cContact records -->
<apex:pageBlockTable value="{!contacts}" var="c" id="table">
<apex:column >
<!-- This is our selected Boolean property in our wrapper class -->
<apex:inputCheckbox value="{!c.selected}"/>
</apex:column>
<!-- This is how we access the contact values within our cContact container/wrapper -->
<apex:column value="{!c.con.Name}" />
<apex:column value="{!c.con.Email}" />
<apex:column value="{!c.con.Phone}" />
</apex:pageBlockTable>
</apex:pageBlock>
</apex:form>
</apex:page>

if you think that answer is right then please tick the answers.
Thanks
Sourabh