The only chat widget allowed on wordpress.com blogs at this time is the meebo widget.
The code is obtained from going to the meebo website and registering there. It’s 3 step process to create your sidebar widget and setup an account with them. After the 3rd step there will be a box to copy the code you need to put into your sidebar widget.
- Log into your WP admin -> Appearance -> Widgets. Click “add” on the meebo widget and it will appear in your sidebar.
- Open the widget and copy the code that you got from meebome.com into it.
- After you have pasted the code in click “Save Changes”.