> HTTrack is absolutely wonderful, but can anyone tell me 
if 
> there is a function which allows us to actually check the 
> total size in megabytes (or gigabytes for that matter!?) 
> of any given web-site, BEFORE we start to download it for 
> offline browsing?
No - this isn't possible, unfortunately. This is actually a 
limit of the HTTP protocol: unlike FTP, you can't "list" 
files and "directories" (there are no files and directory 
in HTTP, only "ressources"), and you can not request the 
remote size of a website.

This isn't an unimplemented feature, but a missing HTTP 
feature (which can not be implemented, by the way, because 
of design choices)