If you're on their mailing list, you usually get 
an email within a few hours after they update.  
Personally, though, I just check out of habit 
every so often... heh.  It means I've caught a few 
updates before the email went out.

As for navigation, there's a better way than the 
description pages... use this link just for cel 
thumbnails:
http://www.animaxis.com/en/shop/celslist.asp

And as for knowing which cels are new from the 
last update, that's just a matter of addiction and 
memory.  *grin*