what is the easiest way to create gifs with rotated pictures (more for ads)
I am not a designer so do not need something complex. :)

I use (Adobe/Macromedia) Fireworks for that, personally. For really complex effects, Flash, and export to gif if that's the format I need.

Microsoft GIF Animator is free and easy for making simple animations . Should do what you want.

Product Description:
Microsoft GIF Animator lets you easily create and customize animated GIF files for your Web site.GIF animations are based on the GIF89a file format, which stores timing information to create the illusion of animation like a cartoon "flipbook". With GIF Animator you can make your animations loop, spin, fade in and out; set the size and transparency of your images; and control a wide range of other options. GIF Animator also features automatic or custom palette creation.

http://en.wikipedia.org/wiki/Microsoft_GIF_Animator

I've used GIF animator before and and as Lumix said it's free and should be more than enough for creating simple banners.

I prefer fireworks but that's not free.

Imageready, but thats not free either

Yea I just use Imageready, but it comes with Photoshop.

But a free option would be to go to download.com, and search through for the gif animators, there are tons and with reviews.