Red Star still makes yeast cakes but it's available only in limited areas . . . and, sometimes, in other areas during holiday baking seasons.

Do a google.com search for "Red Star yeast cakes" for more information . . . and be sure to enter your zipcode at that site to see if (and where) their yeast cakes are available in your area.  Their website also indicates how to convert a recipe calling for yeast cakes to dry yeast. 

--Petrushka

I would just use the package yeast or the yeast in a jar.  One package equals one yeast cake.  The jar yeast-which is what I use - has the conversion on the jar.  You need to leave the jar out of the freezer to let it come to room temperature before using.  Or do you need the cakes for a special reason??

hello friends i think this link will help you for any type of question about yeast.

http://www.baking911.com/pantry/leaveners_yeast.htm#Cake, Fresh or Compressed Yeast

You might be able to find it at a Whole Foods store. Fresh yeast spoils rapidly and is probably the reason why many stores do not carry it. I always use SAF instant yeast and have wonderful results.  

According to the Red Star Yeast website, 1/3 of a 2 oz. cake of yeast is equal to 1 packet (2-1/4 tsp.) of dry yeast.  In other words, it would take 3  packets of dry yeast (2/14 oz. per pkt.)  to equal 1 (2 oz.) cake of yeast.

http://www.redstaryeast.com/lessons/yeast_types_usage/cake_yeast.php

Also:  The conversion table at that website indicates that 1 pkg. dry yeast = 2-1/4 tsp. = 2/3 oz. cake yeast , which is enough yeast to use for up to 1 pound (4 cups) of flour . . . except when the ratio of sugar to flour is more than 1/2 cup sugar to 4 cups flour and an additional packet of yeast should be used because excessive sugar slows down the fermentation of yeast. 

  [AND:  All of THAT explains why my aunt's olde Hungarian Nut Roll recipe didn't  "work" for me:  I should have used 3 packets of dry yeast to substitute for the 1 cake of yeast in her recipe!]