Wow.
Update: Ways and Means has provided the email in question.
http://waysandmeans.house.gov/uploadedfiles/irs_grassley.pdf
In the exchange, Lerner mistakenly receives an invitation to an event that includes Grassley. She leaps to the conclusion that travel expenses were inappropriately offered for Mrs. Grassley. So she suggests referring the senator for an audit.
I think an interesting thing is that Lerner sent this from her Blackberry.
Did that crash too?