1) Use “Instant Play” or “No Download” Linux Poker Sites

To Play Poker on Linux, you first need to have Java / Flash Plugin installed.

To Install Java on Linux, you can visit http://www.java.com/en/download/manual.jsp
Or Install Flash from http://www.adobe.com/shockwave/download/alternates/ 

Important Note: Not all the Linux Poker Sites provide the same features and functions like the windows version have.