Hi ,
I have one doubt that, Should we need Jabber Support server for conversation, Cant we use other web/application Servers?
Please give answer to this question.
Yes there are a lot of public jabber servers you could use. You can find a list of them here: http://www.xmpp.net/bycountry.shtml
If you on the other hand setup your own server it requries some more work from you, but then you have more control, and can use such wonderful features as public contact lists, gateways, logged conversations etc.
/John