To test your freshly installed package, just run (from sqlplus* for example) for example :

--Send a google message
select dbms_xmpp.send_gtalk_plain_text_message('YOUR_GOOGLE_LOGIN',-- your google login
	'YOUR_GOOGLE_PASSWORD',-- your google password
	'Adrien.Sales@gmail.com', -- the recipient(s) of your message (for many recipients, put ; between contacts)
	'test',-- Message subjects
	'hello gtalk from Oracle !') as GOOGLE_RC-- the message itself
from dual;
					

You should get an instant message and a return code = 0.