Step 1. Log into your blog
Step 2. Click Appearance-> Widgets
Step 3. Drag RSS over to your sidebar.
Step 4. Paste http://newsrss.bbc.co.uk/rss/cbbc_news/homepage/rss.xml in where it asks for RSS feed URL
Step 5. Give the widget a title. *optional
Note: PrimaryBlogger users can just drag the CBBC Widget onto their sidebar.