After some license clarifications, the jcr-1.0.jar is finally available in the central Maven repository.
This means that you just need this in your Maven 2 pom.xml to use the JCR API in your code:
<dependency> <groupId>javax.jcr</groupId> <artifactId>jcr</artifactId> <version>1.0</version> </dependency>
See the dev@jackrabbit.apache.org list for more details.