I've decided not to try and push my 4 year old at all. I had intended to do more pre school worksheets with him and get him forming letters but have now decided against it. I too wanted to give him a head start because he will be the youngest in his year. But he really wasn't that interested in worksheets - he did a few, got the hang of drawing up dots and matching pairs etc but that's it. He likes books, he's intersted in things around him, his fine motor skills seem OK - lots of consruction toys in our house. I do believe he will catch up eventually.
When he starts school in January he will not be able to write his name or recognise specific letters. He has no grasp of phonetics ie things that begin with 'buh' or 'luh'. He knows the alphabet song and can count to about 20, knows what 2, 3, 4, 5, sweets look like but that's about it. Gulp.
For better or worse I am putting my trust in his teachers and will back up their methods at home. I am not going to worry about it. I am not expecting things to even out in class until the end of year 1 at the earliest. I have absolutely no idea how he will get on academically. Before my oldest ds started school, I felt he had academic abilty. My yongest ds plays his cards closer to his chest, so I am not so sure.
He is confident and communicates well. He is not too bad at listening. I think, for him, this is all I can ask for for now.
I do agree that if your pre school child really wants to learn the 3 Rs there's no harm in starting - making things a game. I'm sure I did more pre school preparation with my oldest ds, but this was led by him.