Servers? UNIX? Where to start?

I am a web developer learning, JAVA, JSP and JHTML. I want to start hosting my clients’ sites and set up my own server. I have limited financial resources at the time being. I have been looking at ATG’s dynamo personalization server, its the only server I know of that can run JHTML apps. I also want to learn UNIX. I want some way to wrap all these things together so I can learn them simultaneously. Is UNIX the best server OS I can use for JAVA, JHTML AND JSP? Any suggestions on what UNIX OS to choose, and a server for JHTML and JSP, and books or learning tools I can use? Any help and information will be greatly appreciated. THANKS!!!