preventing/throttling successive form posts?

[Jonathan Vanasco]

Does anyone know of a good idiomatic way to safeguard against people  
hitting reload and processing the same info twice?

I'm thinking someone here figured out a series of internal/external  
redirects to keep that from happening.

Right now, I just do a timeout variable in the session -> check if  
someone is throttled, if not process and set a timeout for 30seconds  
if successful.  I'm wondering if there's a more mod_perl way to make  
that happen.