Hi Colleen,
What I usually do is include a calendar file (.ics for MS Outlook or .ical) in the confirmation email.
You can learn how to make a calendar file here: http://community.marketo.com/MarketoArticle?id=kA050000000L555CAC
Here is how to include it in an email: https://community.marketo.com/MarketoArticle?id=kA050000000L9zxCAC
You can also export a Calendar file from Outlook and include the link in your email.
To make an .ICS file from Outlook