In reply to Dominicandave:
The problem with trading the stock market from home is the transaction fees.
£10-£20 per trade. This fee means that each trade has to make more than £20 to be worth your while. So you are limited to long term buy and hold strategies. Which may be fine, but I wouldn't describe it as playing the stock market. If this interests you, most high street banks offer self trade products, where you buy shares in companies that you chose. Personally I would recommend buying Exchange Tracker Funds over managed funds or individual stocks.
If you want to "play" the stock market, the way forwards is spread betting. This is placing a wager on the movement of a stock. Here the fees are usually a percentage of winnings, and the returns are tax free. So someone with a small (less than £250,000) pot can trade regularly, and turn a profit. Most companies will offer a practice account. It is also possible to lose more than your initial deposit.
As stated above, forex has low barriers to entry too.
If you are a small investor, look for investment opportunities that can only support a small amount of capital. That is your one advantage as a small trader. This works because the city doesn't care about an opportunity that can only make £100,000 per year, but you do.
This is a good first book to read about investing
http://www.amazon.co.uk/Long-Short-Investment-Normally-Intelligent/dp/09548...