Here's a quick tip for sending attachments to emails: Write a cover note that at least describes the attachment and provides your full name. Not doing so is careless at best and rude at worst.
I often receive e-mails from people I hardly know whose entire message looks like this:
Re: (no subject)
Date: 1 April 2005, 10:23 a.m. EST
That's it. I suppose this unknown person thinks I can read his mind. The least the sender could have done was write:
Attached is the Midwest Region 2 estimated production schedule for Fiscal Year 2005-06.
Remember that this common courtesy is a sign of respect, so respect your readers!