Parentline Plus courses have a very good reputation, but are only available in certain parts of the country (their website, www.parentlineplus.org.uk, has details, or call their helpline on 0808 800 2222). Further education colleges and church and community groups may also offer local projects. Local libraries are a good source of information about what's available in your area, but your best bet is probably your own GP's surgery or health visitor. They should be aware of what's on offer, and on the feedback from parents who've taken part.

You might also take a look at the National Family and Parenting Institute's online directory of services for parents (at its website, www.nfpi.org.uk). This lists parent support services region by region, together with a list of useful national organisations. The Parenting Education and Support Forum has compiled a useful 'briefing sheet' on what to look for in parenting classes and how to find one in your area (click on 'library and information services' at its website, www.parenting-forum.org.uk).

In the meantime, there's much you can do to help your son.

* Let him mix with other children. Your son won't learn how to mix well with other children unless he has opportunities to do so. He may appreciate and benefit from times when he can play happily and more calmly with older children, whose behaviour may be more predictable and less threatening than children his own age. But it is important he has the chance to play with children of similar age, too. Is there a local mother and toddler playgroup you could go to, say a couple of mornings a week?

This may seem like asking for trouble, but it sounds as though your son has yet to learn that playing with other children can be fun. And there's no better way to learn this than to do it.

If you feel anxious about entering a 'free play' situation just yet, perhaps a more structured toddler activity session, such as a 'music' morning or mother and toddler swimming club, would feel an easier first step towards him mixing more with other children.

* Practice turn-taking. Toy wars - or fear of losing possession of favourite playthings - can lie at the root of much aggression between young children. Most little ones find sharing hard, and many can battle with alarming ferocity over toys of little apparent significance. Precious toys and possessions are often best left out of reach if other children come to play, or left at home on trips to the shops or the park.

Forcing sharing can backfire - kids told they 'must share' may revolt and hang on to their toys with an iron grip. Turn-taking is a much easier concept for them to grasp, and most can manage it with practice and encouragement.

We can help by showing them how turn-taking is done, through games, play rhymes and example: 'You pop the bubble; I'll pop the next'; 'You have a go first, then it will be Nancy's turn, then you can have a go again.'; 'Let's take turns, then everyone has a chance'. Eventually, they'll pick up the basics. Once turn-taking becomes familiar, children can use it to negotiate issues of choice as well as ownership, so it's a great skill to encourage.

* Be clear. Children need to know what's expected of them, where, when and why, and it's our job to tell them. To do this, little children need to be reminded of important ground rules again and again until the message sinks in - 'Remember, we don't hurt each other'.

* Be positive. Even when children seem stuck in patterns of repeated negative behaviour, there will be exceptions and moments when something new happens - when your son walks past another child without pushing or plays without fighting, however briefly. These are the moments to focus most attention and energy. Let him know you've noticed, and tell him why you like what you see: 'Well done. You've learned not to push other children, because you've walked to the shops without pushing once. That's great.' 'You and Nancy played happily. It looked like fun, and I enjoyed watching you.'

Clearly, your son won't understand everything you say, but toddlers do understand much more than we tend to give them credit for. If your expression and tone of voice match your words, he'll soon get the message.

* Be firm. Children need more than clear explanations and positive reinforcement. They are not miniature adults. They need to test, to show aggression, to be unreasonable and to push the limits to know where the limits of behaviour lie. Your son [itals] needs [end itals] you to show your disapproval when he oversteps the mark.

Try to stay relaxed, calm and strong - that way he'll know you're in control of the situation. Leave him in no doubt about what you think about his behaviour: 'I am absolutely not going to have this. That child did nothing to you, and you pushed him. You are not to hurt.'

* Be understanding. Toddlers experience powerful and passionate emotions. Your son's responses may seem extreme to you, but he's feeling a tidal wave of rage and anxiety at the approach of another child and expressing it in the only way he knows how. It's not great for him, them or you, but it is common behaviour. With time, sensitive support, clear guidance and plenty of cuddles, he will grow out of this phase.

These are important issues, and we've only been able to skim the surface. If you'd like more information on tackling problematic behaviour, you might want to take a look at our book, Raising Happy Children. Parents of more than one child may also appreciate information on tackling aggression between brothers and sisters. This is explored in depth in our forthcoming book, Sibling Rivalry, Sibling Love (Hodder Mobius, published on May 16th). Both are reviewed on www.Amazon.co.uk and should be available to loan from your local library. Take a look, too, at the Mumsnet list of member-recommended parenting books. A good parenting course should also provide supporting leaflets and literature.

Whatever route you take, please don't forget your own needs. As parents, we can sometimes become so engrossed in supporting our children that we forget ourselves along the way. Negotiating toddlerdom can be emotionally and physically exhausting, so try to ensure you have sufficient 'time out' to recharge your batteries, relax and think issues through. It's not an indulgence, but an investment for the family

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