1. Go to File\Scripts\Load Files into Stacks… (This option will add all your image in as one file with separate layers).
2. Add all your images that you want in the animation.
3. Open the Animation Palette from Window\Animation
4. Click on the Flyout Menu on top right corner of the animation window and select Make Frames from Layers
5. Adjust the timing of each frame by selecting the 0 sec. on the frame

To save as animated Gif
Go to File\Save For Web & Devices Choose your Image Settings and Looping Options
Click Save.

To save as a Movie for Flv, IPhone, IPod, Quick Time, MPEG4 and so on
Go to File\Export\Render Video Choose your Settings.
Click Save.