Gmail has (finally) added additional functionality making it easy for you to attach multiple attachments to an email. Google tend to stay away from most things flash unless absolutely necessary but in this case they’ve made an exception, and i’m grateful.
Simply attach a file as normal and select the multiple files that you are looking to add as attachments – pretty straight forward.
note. If it doesn’t appear to be available on your GMail yet, try logging out and in again.