are you in the UK? If so, look up Inland Revenue in the phone book, and ring your local office. they will send you a form to complete, giving details of the work you intend to so. This form will also give you information about paying National Insurance Contributions, which you will have to do if you are working free-lance. You must keep a record of all your income and expenditure and then complete a tax return after the tax year end. Any tax you owe will be payable on 31 January following the end of the tax year, with a payment on account for the next tax year also being due on that date and the following 31 July. You must therefore keep a proportion of your earnings aside. You say a "little work", you can earn �4745 a year before you are liable to tax, but this figure includes all income such as pensions, state pension and most(but not all) state benefits, also income from savings and investments.