The WongSK blog has a excellent tutorial that will help you add GTalk to the sidebar panel in Opera. To add GTalk to the Opera sidebar, follow the simple instructions below.
- Enable Panel view in the Sidebar, you can do this by click the tools icon in the left hand side corner of the browser.
- Right click the panel and click customize.
- Click on the Add Web Panelbutton.
- Give the panel a name and add the GTalk gadget URL ( http://talkgadget.google.com/talkgadget/client?fid=gtalk0&relay=http://www.google.com) as the address and click on Ok button.
Once you have followed these steps, a new icon will be displayed in the panel, clicking on the new icon should display GTalk in Opera sidebar.