Contact cont = new Contact(LastName = 'TestLast');
insert cont;
Id defaultRtId = [SELECT RecordTypeId FROM Contact WHERE Id = :cont.Id].RecordTypeId;

Account a = (Account)Account.sObjectType.newSObject(recordTypeId,true);

Map<String,RecordTypeInfo> infos = Account.sObjectType.getDescribe()
    .getRecordTypeInfosByDeveloperName();