public class ListExample {
 public list < account > myaccount {
  get;
  set;
 }
 public ListExample() {
  account a1 = new account(name = 'sam', type = 'prospect');
  account a2 = new account(name = 'ram', type = 'prospect');
  myaccount = new list < account > ();
  myaccount.add(a1);
  myaccount.add(a2);
 }
 public pagereference save() {
  update myaccount;
  return null;
 }
}

<apex:page controller="ListExample">
<apex:form >
<apex:pageBlock >
<apex:pageBlockTable value="{!myaccount}" var="a">
<apex:column value="{!a.name}"/>
<apex:column value="{!a.type}"/>
</apex:pageBlockTable>
<apex:commandButton value="save" action="{!save}"/>
</apex:pageBlock>
</apex:form>
</apex:page>