For both banners and gifs, you have to have Photoshop Cs3 Extended. The alternative for gifs is Image Ready 7.0 (comes with Photoshop 7.0) and VirtualDub (free). But i personally recommend Photoshop Cs3 Extended. Its pricey but good. PM me for alternative 'buying' source

As for the pointers, i suggest you pick up some banner tuts online. There are gazillions of them on the net so they won't be hard to find. The best source in my view is DeviantArt. My personal recommendation is that you mess around with the photoshop, u know randomly and all to get the feel of all the ups and downs. When u get the hang of it, you can then use the the tutorials. I did the same.