ajax4jsf 1.1 is a too old.
This project was merged with RichFaces UI library at September 2007.
Latest release is RichFaces 3.1.3.GA , released at December 17 2007 . You can download it from http://labs.jboss.com/jbossrichfaces/downloads/ .
This is a Maven project, so it deployed into Jboss repository http://repository.jboss.com/maven2/ , with md5 and sha checksums.
In the case of Maven builds ( or with Maven dependencies Ant tasks ), they should be used automatically with artifacts downloads.
For a manual verification you can use checksums from http://repository.jboss.com/maven2/org/richfaces/ui/richfaces-ui/3.1.3.GA/
For now, I want to stick with Sun JSF 1.2 RI. Can I use Ajax4jsf with Sun JSF 1.2 RI ?
I want to added only limited AJAX functionality.
RichFaces works with JSF 1.2RI the same way as Ajax4jsf used to do.
With RichFaces 3.1.3 you can use as limit AJAX functionality as you want.