This e-mail is a phony. The IRS does not send unsolicited e-mail about tax account matters to individual, business, tax-exempt or other taxpayers. See the article at http://www.irs.gov/newsroom/article/0,,id=178061,00.html for more information about these scams.
If the deposit was to be made on 05/02/08 it may be that you bank has not yet processed it yet. check back Monday or in a few days.
I hope this helps.