The Eclipse Callisto project’s aim is to eliminate uncertainty about version compatibility by releasing about 10 different eclipse projects at the same time. With the 3.2 Eclipse version a Callisto update site is preconfigured. One can choose features to add like the WTP for web development and the dependencies are automatically selected. But I could not get this to work satisfactorily.
Now there is an alternate way to get the Callisto stuff. Many companies are offering Eclipse bundles. Check out the Callisto Member Downloads Page. Thanks to the Eclipse Ecosystem blog for pointing this out. I personally prefer the Yoxos on Demand. With this I can pick and choose the exact projects I want.