Well, there seems to be no built-in gadget to insert a table of contents of your blog. The ‘Blog Archive’ gadget can be customized a bit but that does not suit my needs. Luckily there is a simple way to do it:
1. Go to http://feedburner.com/and sign up for a free account. You can use your existing Google account.
2. Use your blog address as a feed.
3. Then, click on the Publicize tab. Then click on Buzz Boost. Configure the settings so that it’ll only show the post title (e.g. uncheck everything). Then click ‘Activate’.
4. You’ll be given an HTML code. Go to your blog settings and create a gadget containing this HTML code.
5. Done! Now you’ll alwayshave an updated TOC for your blog.