Since 2.5 (or the .com equivalent is at this very moment coming to a .com blog near you, I thought I would post a bit of a caution regarding text widgets and working with them.
If you have text widgets with code and such in them on your blog, open each one of them, copy everything in it and paste it into a text file for safe keeping. The reason I say this is that if you remove a text widget from your sidebar, and then decide you want to put it back, when you "add" one back in, it will come in blank with nothing in it. Hopefully WordPress will work on the widget admin area and take out some of the present shortcomings.
Since you cannot see more than one sidebar at once, moving a widget from one sidebar to another is more involved.
1. Go to design > widgets
2. Click on the text widget edit link
3. Copy the content of the widget to the clipboard
4. Click the remove button
5. Click the “Save Changes” button
6. Select the target sidebar from the pulldown
7. Click Show
8. Click “Add” on the text widget bar in available widgets
9. Click edit on the text widget in the sidebar panel
10. Paste the content into the widget text area
11. Reenter the title (if one is desired)
12. Click “Change”
13. Click “Save Changes”
If you are moving more than one, you will have to copy the stuff in the widgets out to a text file. And when working with multiple edits in a sidebar, press "Save Changes" after each widget edit, or the changes may not be saved for all of them.