As of April 4, 2005 the SANS Internet Storm Center has raised their alert level to Yellow following a rash of active DNS poisonings. 

The infected DNS servers are re-directing users from popular sites such as Google or American Express to malware infecting advertising sites. According to the ISC presentation on the attack, it is believed to be linked to known spammers and malware distributors. 

The full presentation of information up until this point can be found aaaahhhhhh!