The data that was accessed includes usernames, e-mail addresses, hashed passwords, registration IP addresses, and some other less interesting stuff which was forum related.
In a post titled Important Notice - Security Breach, Android Forums administrator "Phases" said that the attack was a bog standard one using a known vulnerability.
The server has been checked for dodgy code, and hardened against similar attacks.
At the moment the advice is for users to change their passwords and if you have the same mail address and password combination elsewhere, you should change it there too.
Apparently no other sites in the network appear to have been accessed.
The organisation believes this was an e-mail harvesting attempt and the hackers were looking for e-mail addresses to spam at a later time.