Downloading JsOrb
Everything you need to get the latest version of JsOrb is available on the download page. JsOrb is licensed under the LGPL, so you can use it under the (very limited) restrictions the LGPL places upon you.
Currently JsOrb is configured using the Spring framework, so you'll need to get a copy of it here. (Spring's a wonderful configuration tool, but an enhancement to JsOrb will soon make Spring optional in case you'd rather not use it).
The last library JsOrb requires is dom4j, which is used by the XML marshaler. This component too will become optional in a future release when non-XML-based marshallers are available, but for now you can download it from the dom4j download page.