Dottman,
Email traffic always counts towards your bandwidth usage. Any and all pieces of transferred information including files, webpages, email, etc. are considered bandwidth usage as they require bandwidth from the server which hosts your domain. Though in most cases email bandwidth is rather negligible as most emails, unless containing attachments, are very very small in file size. Also in the future many of your questions can be found by visiting the reseller page at
http://www.hostony.com/reseller.html and simply pointing your mouse over the information icon to the left of each general feature. It will give you some more indepth information as to what each feature is as well as what is included with it. Hope this helps you with your question.
Sincerely,
Aveed Khaki
Ipsilonblue.com (soon to come)
P.S. didn't know if I was supposed to post under guest or not... sorry for the second post 8)