With your hands and brains. Use Flash or gif. Flash is better looking, but browsers does't like it. Gif is old look but works anywere. If yo willing to go further use Flex, but probably only few already started to use it yet.
there's alot of banner templates out there but but designing a banner from scratch is much better.. you should watch/view/read photoshop tutorials and get alot of banner design inspiration.
you can download the photoshop banner tutorials & watch step by step then u can create easily your own banner.
I would try to stay away from flash and learn Photoshop. If will come in handy for your future projects as well.
If you want to create a banner watch in youtube it will help you create a banner. And if you want a website template visit our website at netmusketeer.com
To make attractive web banner you must need to use your creativity. You need to create document on photo editing software according to your banner size. Then you need to use brush, fonts, your best imagination etc. Then you will be able to create a nice ans attractive web banner. Also if you want to animated web banner you may use Adobe flash software.
That's right, you have to come up with your creativity. You can learn to navigate photoshop (or, whatever) by 24hour, but can't adopt the skill to sketch your exact imagination into the document. If you really want to make it attractive, you have to go for banner professionals.