decompiling DEX into Java sourcecode

Are there any tools or recipes for turning Android DEX (VM bytecode) files into corresponding Java sourcecode?

Adding Google Guava to Android project - significantly slows down the build

After adding Google Guava r09 to our Android project the build time increased significantly, especially the DEX generation phase. I understand that DEX generation takes all our classes + all jars we depend on and translates them to DEX format. Guava is a pretty big jar around 1.1MB