Both SANS, a security research organization, and security vendor F-Secure are reporting malicious e-mail targeted to pro-Tibet groups. The attacks include a legitimate-looking e-mail body with photos or text about Tibet and one or more malicious attachments, often disguised as legitimate files (e.g., a PDF that exploits a vulnerability in Adobe Reader). SANS reports that some of the malware is not detected by popular anti-virus applications.
Those who are on mailing lists of Tibetan activist or support groups should be especially vigilant, and the usual advice of not opening e-mails or attachments that you are not expecting, or that come from unusual sources, applies.