Will it be possible for windows xp or windows server 2003 to support net.tcp for WCF, well it works in windows server 2008 as IIS 7.0 supports net.tcp,but is there anyway for IIS 5.1 or IIS 6.0 to support net.tcp,is there any workaround for this?
No, you will have to host it yourself (windows service for example) to use net.tcp. See this article for a list of hosting options and what transports they can host.