http://www.homebrewtalk.com/freezing-yeast.html
I think Im going to do this. Ive a pain my arse with the short lifespan and slow ramp up from slants
If it works well it'll be a very useful technique. I'd looked at doing similar myself recently so I'll be interested to see how it works out in practice.
I've done it with success, still have some vials frozen going on two years now. Must restart them and see if there's still life left in them!