Was anyone successful in getting their after insert trigger on Attachment working? I don't see any debug logs for the trigger when I try to invoke from the UI
 
 Updating post to add my code:

    trigger AttachmentTrigger on Attachment (after insert) {
       Map<id,List<Attachment>> taskAttachmentMap = new Map<id,List<Attachment>>();
        for(Attachment attachment: [SELECT Body,BodyLength,ContentType,Description,Id,IsPrivate,Name,ParentId FROM Attachment where Id IN :Trigger.new]){           
            String text= String.valueof(attachment.ParentId);
            if(text.startswith('00T')){
                List<Attachment> la = new List<Attachment>();
                if(taskAttachmentMap.get(attachment.parentId)==null){
                    la.add(attachment);
                }else{
                    la = taskAttachmentMap.get(attachment.parentId);
                    la.add(attachment);
                }
                taskAttachmentMap.put(attachment.parentId, la);                     
            }
             
        }
        
        List<Attachment> attachmentsToInsertonOpp = new List<Attachment>();
        //Find all tasks that are associated to opportunities
        if(taskAttachmentMap!=null){
            for(Task t: [select id, whatid from Task where id IN :taskAttachmentMap.keyset()]){
                    String text1 = String.valueof(t.whatid);
                    if(text1.startswith('006')){
                        for(Attachment att:taskAttachmentMap.get(t.id) ){
                        	att.parentid=t.whatid;
                            attachmentsToInsertonOpp.add(att);                        
                        }
                    }
            }           
            
        }
        
        //Now insert attachments
        if(attachmentsToInsertonOpp.size()!=0){
            insert attachmentsToInsertonOpp;
        }
        
   
    }