So my game I am developing (I have not yet released anything as I am not yet ready to release anything of it to the public) makes use of animated cutscenes with voice acting. The problem is is that with the game and all of the video/audio I am afraid my game may be too big for the app store. So I was wondering if there is a good compressor for audio/video that I can use for my app but have it still look and sound appealing.
What type of audio files are you using and what is the sample rate? You can use any audio editor (Audacity is free) to reduce the sample rates and come up with a balance of quality/file size that you are happy with. While ideal, you probably don't need 44100 Hz stereo audio files, and cutting them to mono or even 22050 Hz mono will reduce the file size tremendously.
The iPhone/iPod touch has a built-in H.264 decoding chip, so I think that would be the best compression codec to use.
For audio, you can convert standard WAV to lossless CAF (compressed AIFF) on the Mac (it has a built-in converter from the shell) that will cut your audio file sizes down to around half or more with no loss in quality. For video you can encode to h.264 with a low bitrate; the video will probably have a lot of block noise but it will keep file sizes down if you're really worried about that.