When we started doing breakfalls the first one we learned was backwards falling.
This is unbeleivably easy, all you need to do is stand upright confortably legs apart about shoulder width take your foot and place it behind you toes pointed behind (top of foot to mat) lower yourself to your knee, then to your bum (basicaly sat here) then roll backwards to the OPPOSITE shoulder to the foot you started the technique with, when you come over you should be able to stand up with ease, and dont forget to Tuck your chin to your chest.
Its really that simple for a backwards Ukemi, try practacing, slowly at first then as you build up confidence faster.
(WARNING) One important thing to remember whenever your doing a technique and your going to go down backwards ALWAYS, always fall with the foot NEAREST your apponant.
you must remember that, then again if you dont you'll know about it
As for forward breakfalls, it is perhaps good to learn your Shikko (Knee walking/Samurai walking) before you do them.
I'd also rather not describe them to you here, just incase you misunderstood and do yourself an injury, suffice to say i imagine my body as a hula hoop (for those who remember them) going from my hip to my hand then the back of my arm and then my back itself finaly arriving back at my hip.
It helps to think your not a weeble (they wobble but they dont fall down) do forward Ukemi with your instructor, i'm sure they'll make you take a whole class of it. (mwuhuhahahahahaha)
Actualy our kid mentioned this the other day,
she came to a class to watch us and saw us all doing what she thought was training to be in the circus. (lesson on breakfalling)
she was very amused.
btw. our kid is a manchester euthomism<sp?> for sibling.