First of all, you will need to create your banner in Photoshop, Photoshop Elements, Paint Shop Pro, or another image editor of your choice. If you've never done this before, stand by, I'll give some links and ideas in another post. For now, you can experiment with just about any image you have handy.
The one considersation, for now, is the size of the banner image. At http://www.nelalive.net, my banner immage is 900 pixels wide by 200 pixels high. You could just as easily use an image that is less wide, and allow a background color to fill the unused space.
So here goes.
1. Crop or resize A COPY of your selected image so it is not more than 900 pixels wide and not more than 300 pixels high. Save the image COPY as a JPEG. (I empathsize "COPY" since it's never a good idea to muck up a prefectly good original image without first making a backup copy)
2. To to http://www.typepad.com -- sign in
3. From the Welcome Screen, click the Weblogs tab
3. Click Design
4. Click Change Theme
5. Then Select the Custom Theme Button
6. Under "Page Banner" click, Edit This Element
7. A "wizard" box will pop up. Place a check mark in the box under "Optional", browse your computer for the image to upload (exactly the same way you do when uploading images to Active Rain). Then click "Save Changes.
I did my custom banner for my neighborhood blog in (gasp) publisher. Using some of the programs you recommended, Cheryl, would probably be much easier and a more professional result!