So, this pretty lines of ruby code ( using xmpp4r gem ), change your google_talk status and send chat_message to your friend. Thank you, @Arkan!
require 'xmpp4r'
# init jabber client
client_jid = Jabber::JID.new( 'your_email@gmail.com' )
client = Jabber::Client.new( client_jid )
client.connect 'talk.google.com'
client.auth 'your_gmail_password'
# change google_talk status
client.send( Jabber::Presence.new.set_show( :chat ).set_status( 'Your New GoogleTalk status' ) )
# send chat_message to friend
friend = Jabber::JID.new("your_friend_email@gmail.com")
message = Jabber::Message::new(friend, "it's chat message").set_type(:normal).set_id('1')
client.send(message)
I love ruby ^_^ !