IT security firm Sophos now has detailed info on the attacks and a video describing them: Twitter Phishing spam wave

After the first attack wave, however, the phishers are now using the compromised accounts to send out spam, which resulted in a huge amount of Viagra-related messages on Twitter, which read something similar to this: “Get bigger and have sex longer. go here”, followed by an address that leads to a sexual enhancement site.

Once again, if you see unusual messages (similar to the examples above) sent from your Twitter account, it may mean it has been compromised, and you should change your Twitter password immediately.