Let's start with one little bookmarklet. This one will add selected text to Yahoo! Notepad.
1. Drag the link !note to your Bookmarks Toolbar.
2. Select some text, click the bookmarklet, sign in (if you aren't already), choose folder and save your note.
Updated: Now it works with IE6 SP2 and you can drag it to the Links Bar. Thank you, subject m. (See comments for details.)