Theoretically, pokerroom.com should work, since there is no download. However, I tried it and it failed. It just gives me the blank java app window (with the little cup of coffee). I am running RH 9.0 with the latest version of Java I could find (1.4.1_02).
I DL'd Blackdown Java and ran it. It gave me the license agreement, but did not appear to ever actually uncompress to anywhere. The .bin for it is sitting in my /usr directory.