I'm currently working on making my Arduino eclipse plugin Arduino IDE 1.5.2 compatible.
It is a complete rewrite for several reasons. But technically the main reason is that I wanted to have the Arduino Libraries and the sketch in the same project.
I have been willing this since I started working on Teensy compatibility. However CDT -The core C++ functionalities in Eclipse- does not support it.
So I have been working hard to make this work. For people knowing about CDT: I had to build a makefile generator; 2 name providers; a dependency calculator and a language provider.
It has been a rough ride and plenty of long nights. It all works now on my system but there is a major drawback ...... It only works in Juno.
Another drawback of this new version is that it is not downwards compatible on the workspace and arduino IDE level.
The workspace level is quite understandable as the project setup in eclipse is completely different.
To get it running with pre 1.5.2 versions you will need to add a correct platform.txt file to the hardware folder. But .... it has not been tested yet.
If you are interested in doing alfa testing please contact me with your available hardware and OSses you can test.