If you want to start tweeting with him now, visit his twitter page or tweet him: @InsultOBot.
If you want to learn more about how he works, you can visit InsultOBot.com.
Here is the quick intro to Insult-O-Bot: Tweet the word "nominate" and some friends' handles, and he will insult them for you. Tweet the word "immunity" and he will put you on his "immunity list" where you will be safe from his insults. Insult him, and he will insult you back. Insults are customized to fit the user. He slowly learns more insults the more you insult him, so if you would like to contribute, please visit his twitter page call him horrible things.
Here are a few of his latest tweets: