The latest "billing statement" from the e-mail looks like
this.

The attached binary file is now detected as
Trojan-Downloader:W32/Nurech.AS since database update
2007-02-19_09.
Similar to the previous variants, the recipient is asked to verify
the billing statement by opening the file using Adobe Reader. This
time, however, recipients are assured with the digital signature
mumbo jumbo.
When in doubt, contact the possible source. In this case, your
nearest IKEA representative.