hi, can someone please tell me how i need to deal with .rar files and zips files. sometimes my mac unzips a zip file with a double click. sometimes it says unix extractable file. sometimes if i extract the zip on a pc, mac wont recognise the extracted file. is a utiltiy or app built into my macbook that deals with these? or do i need to buy a third party extracting utility?? im running the latest leopard. thanks.