Exploded Isometric Effect

There's some utilities over at AEScripts.com, but as Rick said, AE doesn't have much in the way of native support for ISO animation. It mostly just comes down to drawing your artwork suitably and then slicing it up so it can easily be animated in a standard 2D process, if you don't want to put up with genuine 3D models and 3D programs. Depending on what type of isometric style you are after, even the latter may not be an option as some of that stuff uses forced foreshortening with fixed ratios, not physical projections. really depends. An example of your desired outcome would indeed be useful to judge the situation and advise.

Mylenium

After Effects does not have an Isometric camera so you'll have to deal with a little perspective. The easiest thing to do would be to create a 3D model and do your animation in a 3D app. If you are using AE alone you will either have to animate flat artwork which requires a lot of skill as an illustrator and an animator or create artwork for each side of your model, arrange them in AE's 3D space and then animate the position of each side and use an AE camera with a long lens to reduce the perspective effect.

There are dozens of ways to do this kind of thing. If you have an example you could share it would be helpful in pointing you in the right direction.