Video chat without registering
Upon activation, go to Settings » Neat Skype Status, enter your Skype ID and save settings. Go to Appearance » Widgets and drag and drop Neat Skype Status v1 widget to your sidebar. Step 3 Open Skype on your computer and sign in with your ID. Under Allow IMs from option check anyone so that people who are not in your contact list can chat with you.
After that check the option If you are using the full screen desktop Skype App on Windows 8, then take your mouse to the right corner of the screen and then click Settings » Options.
However, most of them are paid and the free ones are not so great.
Using a web based app you can add IRC chat in your Word Press site. Open the published page and you will see Kiwi IRC in action.