Judging from the reports, a probable new Bropia variant is spreading over MSN Messenger like wildfire. If you receive a message similar to: "omg this is funny!" followed by a hyperlink to cute.pif (located at a random domain) do NOT click the link and inform the sender he or she is infected. You can take it as a general rule never to accept or click .pif files.
UPDATE: Sorry for double-posting this. Like Sean advised: "All messers should make sure their anti-virus software is up-to-date."
UPDATE #2: Kara reported the following variation to the message sent: "[domain.com/subdirectory/]omg.pif lol! see it! u'll like it"