In general, attachments are a bad idea. (See Letter in support of science.)
It is much more preferable to create a WWW page and email the URL.
excerpt from Houston Amateur Television Society (HATS) digest 671
Please DO NOT SEND MIME ENCODED DOCUMENTS TO THE LIST. Please send only plain text documents. Do not use the "attach file" function of your mail tool. If you want to include a document, just type, cut and paste, or insert the text into the body of the message.
AOL and Microsoft mailers are particularly prone to sending MIME encoded information with associated headers that cause problems for recipients. ListProcesser (the list server software) does not handle the way those mailers put an extra new line in the middle of one of the MIME header lines. As a result, many mail clients hang when the reader is trying to retrieve email from their service providers.
By default, Microsoft Outlook includes the body of a message twice, once in plain text and once as MIME encoded HTML. Please choose a "text only" mode when posting messages to the lists.
Again, please post messages as TEXT ONLY.