Single executable jar can be downloaded from here.
Aequo is meant to work on any platform where Java JRE 1.5 is implemented. It is developed on Linux OS and regularly tested on OS X (10.4). Currently some unimportant features might not work on some more exotic platforms (like inovking browser from the Java code) but that won't impare functionality of the program.
Aequo is licensed under EPL V1.0.
Source code is available here.
Developers can find JavaDocs here