Bradley Friedman of Hashbang Productions has released a preview of an upcoming tweak for the iPhone that allows for user animation customizations. Animation adjustments can be made for banners, alerts, and for the appswitcher. Zoom styles, animation speed and test banners are available for trying out different options.
Animer does not require a respring between customizations, making it very user friendly for trying out different styles/settings. Animer should be available shortly in Cydia and is expected to cost $0.99.