Hi Neil,
We are putting together a TypePad guide, but here's a quick summary of how to do this:
1. Log into Typepad
2. Select your weblog
3. Click the "Design" tab
4. Click "Manage your saved designs" on the right under design shortcuts
5. Select the checkbox of your current design and click the "Convert to advanced" button. (You can undo advanced later because it clones the design)
6. Confirm you want to convert to advanced.
7. Your new advanced template will be in the list. Click 'Apply' on the right of the advanced template.
8. You should now see a list of templates you can edit.
9. Click on sidebar and edit that.
10. Place the javascript directly below the text that says "<!-- sidebar -->" at the top.
You can also put it lower down if you'd like, below the <MTBlogIfArchives>
I hope that helps. We will put together a guide soon with screenshots. We're also hoping to get this automated with typepad.
Regards,
Mark.