Stargate is the new RESTful web service front end for HBase, which is planned to replace the old REST server. Some new features include serving up data in XML, JSON, and protobufs, as well as having an API that's better integrated to REST. Check out http://wiki.apache.org/hadoop/Hbase/Stargate for more information.
I rewrote the existing 'hbase-ruby' client to use Stargate and released it on Github/Gemcutter.