Found a couple news stories which had my twitter-sense tingling:
Twitter Hack Raises Flags on Security (NY Times)
Hackers Target Twitter (Business Week)
As it turned out, there was no cause for alarm, as they're talking about Twitter-the-company, not twitter-the-web-service. The short version of both boils down to "a Twitter employee's email password got cracked, which let the Bad Guys access their Google Docs account". That's not news, it happens every day, but at least the papers took the opportunity to tell the public about good password-handling practices.