It's been awhile, but I swear once upon a time someone posted up a how-to showing their
mods to a military water can so that it had a press-to-pump type faucet in the lid.
searching...... not finding!!!

LINK
the pics are down but thats the link.
Thanks!
From that link I was able to find the following link with pics:
Water Can Mod
I revisited this last year and would like to do a couple, but the expense of the pump is a deal breaker for me.
Is there an decent pump in the $30-40 range?