Using symmettric keys in GPG

[Varun Pitale]

I want to use GPG in our office, and want to use symmetric encryption for 
sending files.. The reason being the files are too big (> 400 MB) and to 
encrypt them using public-key becomes too slow.. How can I generate 
symmetric keys using my choice of the algorithm and will the receiver 
automatically find out what algorithm I am using or does he have to make 
changes to his GPG too?/ 

-- 
"Beware of programmers carrying screwdrivers."
-- Chip Salzenberg