Thanks your Post Rajiv .i am using your code but this code not saved display the Errors.

 i.e  Initial term of field expression must be a concrete SObject: LIST<Lead> at line 20 column 12

Trigger

======

trigger ConvertLead on Lead (after insert, after update) {

List<Id> accountIds = new List<Id>();
List<Id> contactIds = new List<Id>();
list<lead> leadobject = new List<lead>();

for(Lead led: Trigger.New){
if(led.isConverted == true && led.Lead_type_picklist__c =='Broker'){
if(led.ConvertedAccountId != null && led.ConvertedContactId != null )
leadobject.add(led);
accountIds.add(led.ConvertedAccountId);
contactIds.add(led.ConvertedContactId);
}
}
Map<Id,Account> accountMap = new Map<Id,Account>([Select Id from Account where Id IN: accountIds]);
Map<Id,contact> contactMap = new Map<Id,contact>([Select Id from contact where Id IN: contactIds]);
List<account> accountinsert = new List<Account>();
List<Broker__c> brokers = new List<Broker__c>();
for(integer i=0; i<leadobject.size(); i++){
Id accId = leadobject.ConvertedAccountId; //at line 20 column 12 ERROR LINE
Id cId = leadobject.ConvertedContactId;   //at line 20 column 12    ERROR LINE
Account accountobj = accountMap.get(accId);
Contact contactobj = contactMap.get(cId);
Agency__c ag = new Agency__c();
ag.Name = accountobj.Name;
ag.Mailing_Address__c = accountobj.BillingStreet;
ag.City__c =accountobj.BillingCity;
ag.State__c = accountobj.BillingState;
ag.County__c = accountobj.County__c;
ag.Zip_Code__c = accountobj.BillingPostalCode;
ag.Account__c = accountobj.ConvertedAccountId;
ag.Phone__c = accountobj.Phone;
accountinsert.add(ag);
Broker__c b = new Broker__c();
b.Name = contactobj.Name;
b.Agency__c = accountobj.id;
b.Contact_ID__c = contactobj.Id;
brokers.add(b);
}
if( accountinsert.size()>0)
insert accountinsert;
if(brokers.size() > 0)
insert brokers;
}

how can solve this problem pls help me....................