Recently I co-presented a webinar about how to integrate Java Spring Apps on Heroku with the Force.com / Salesforce.com REST APIs. Check out the recording:
<iframe width="640" height="480" src="http://www.youtube.com/embed/GRLzYwtzWqU?rel=0" frameborder="0" allowfullscreen></iframe>

I've also created [an in-depth walk through][1] of the [code example][2] and step-by-step instructions for setting up and deploying the example Java Spring app on Heroku. [Check it out][1] and let me know how it goes.

 [1]: http://wiki.developerforce.com/page/Integrating_Java_Spring_Apps_on_Heroku_with_Force.com_REST_APIs
 [2]: http://github.com/jamesward/hello-java-spring-force_dot_com