The Feeds module allows you to display links to the most recent posts from other sites - including your own blogs - in the sidebar.
Do you have multiple blogs within your TypePad account? If so, you can use the feed from one blog to display links to your most recent posts on other blogs within your account.
Grab the feed for the site you want to add to your sidebar and go to Design > Content. Select the Your Feeds category, choose the RSS/Atom Feed module, and click the Add This Module button.
Enter the site's URL or feed. Please note the feed needs to be valid in order to be picked up. Click OK. You'll be prompted to edit the module Title and number of entries to display. Click OK when complete.
After arranging the modules in your content, click Save Changes to update your blog.
The Organize Content article in the Knowledge Base has more information on the Feeds Module.
If you are using Advanced Templates for your blog's design, the template tags for the module are available in the Knowledge Base.