You can join the chat with an IRC client such as mIRC (Windows), Colloquy (Mac OS X) or ChatZilla (Firefox Add-on).

Server: chat1.ustream.tv
Channel: #aLAneDgEheaD

Or
Join using the Ustream Flash Chat (Ustream account required).

Chat Rules

These are the rules each viewer is expected to follow in the live chat room. Failure to follow these rules will result in a warning, kick and/or ban, depending on the severity.

No Offensive Language - Offensive language of any type will not be tolerated. This includes but is not limited to, swears, directed insults and discriminatory comments (race, gender, culture, religion, sexuality, etc.). Suggestive statements are not appreciated either, nor are attempts to bypass the bad word censor.
Be Respectful - Do not insult or bother anyone. We do not appreciate it when anyone is picked on, no matter who they are.
No Link Spam - Questionable links or material are a sure way to get banned quickly. Posting your stream, site, YouTube, etc. links just to get clicks is not allowed. This also applies to chat channels; do not post outside chats in any attempt to get more members.
Do Not Spam Comments - Posting the same thing over and over again will not get you noticed, and you are more likely to be kicked than get a reply from anyone.
Do Not Stress Words - Please avoid stretching words, posting in all capitals or using excessive punctuation. For example, you may get kicked if you repeatedly post something similar to the following: "Noooooooooooooooooo!!!" or "I LOVE THIS GAME!!!!!!!!!!!! IT ROCKS!!!!!!!!!!!!"
Be Careful of Your Privacy - This is a public chat, which is being viewed by many people you do not know. It is recommended that you never post your real name, age or contact information in the chat, or respond to any direct requests to do so. Also be careful about information such as school or work location, and anything you feel even the slightest concern over.

Are you seeing commercials in the streams when you open them up? Want to remove them? Here are some steps to block them.