Jimmy Smits makes a couple of small cameo appearances in Episode II Attack of the Clones as Bail Organa. Did you miss that? Did you miss Episode II entirely? :) He has a slightly larger role in Revenge. Actually I don't think Smits and Christensen are in any scenes together but I am sure someone will correct me if I am wrong.
Yeah. After Kenobi and Skywalker rescue Palpatine at the beginning of the movie, Smits is in the delegation. I believe he and Christensen have some dialogue, but I may be wrong.