Broadcast news in America and Oz (8)
I believe the answer is:
announce
'broadcast' is the definition.
(thesaurus)
'news in america and oz' is the wordplay.
'news' becomes 'nn' (an abbreviation for new written twice).
'in' indicates putting letters inside.
'america' becomes 'a' (common abbreviation - e.g. in organisation names).
'and' means one lot of letters go next to another.
'oz' becomes 'ounce' (oz is the abbreviation for ounce).
'a'+'ounce'='aounce'
'nn' inserted within 'aounce' is 'ANNOUNCE'.
(Other definitions for announce that I've seen before include "Declare her weight" , "Broadcast (information)" , "Declare, proclaim" , "Formally declare" , "Reveal" .)