The thing with JP is (and really, an effective phonics programme) is that it should NOT rely on things the letter begins with to associate the sounds.
In JP, the sound /n/ is represented by an aeroplane story, action and sound - because saying 'nnnnn' sounds a bit like an aeroplane engine. It's got nothing to do with what begins with 'n' or anything - this can be very confusing for children.
Although we take for granted the 'a is for apple, b is for ball' etc, it is not plainly obvious to children what this is all about.
The SP/JP way, they are aware of the sound 'nnnn' by a fun story/action etc and then learn that it can be written 'n' 'nn' and 'kn'
The pictures offer an immediate reminder as to the action and sound, without the child having to then work out what the initial sound is if it is not immediately apparent to them.
The picture associations with the letters of the aplhabet is also limiting because it associates one letter with each sound, which is far less that actually occurs in our written and spoken word. 's' might be for snake, but what about when the letter 's' is in mash and pens and when the 's' sound is in 'face?'
With the JP method, these seemingly tenous and ridiculous sounds/pictures/actions etc are introducing children to ALL the speech SOUNDS then beginning the process of matching ALL the spelling representations to them.
puddingandpie - you said "Do you spend a lot of time going over letters etc with your son? I feel guilty that i don't spend enough time with reading with my 4.5 year old" which I thought was really sad, because you shouldn't have to be the one going over letters with your child or feeling guilty if you haven't - it should be the school's job, and hopefully with the new report that synthetic phonics should be at the heart of the literacy curriculum, hopefully the school will be making a more effective job of this soon. However, if you feel your school is not tackling this right, it sadly is up to us to do it instead...