BBC World Service radio frequency changes
for North America have not yet been announced.
The BBC web site indicates you can have the info
e-mailed to you (see bottom of this web page):
http://www.bbc.co.uk/worldservice/schedules/onair/
> You can also receive details of changes in radio frequencies by email.
them you are interested to know about changes
in shortwave frequencies.
I presume they will (eventually) e-mail the frequency
changes to you.
Geoff