Sun Inc Second Life Browser Viewer (Beta)
Unfortunately, this java-based viewer is written in Japanese, so let me introduce. At first, visit the website and click the yellow button to launch the viewer.
After logging in, you can find text field to chat and "say" button next to the field. 4 buttons below are "Close","Map","Search" and "Logout". Use the cursor key to move around, page up key to fly. You can't control your camera position.
Right/left click is enabled. This means that you can touch objects, show the pie menu and show edit dialog. Touching key "i" will let you show your inventory.
It's amazing that you can use second life with real time rendering within a webbrowser if you only have low spec PC.