To have your ad appear in our Sponsored Links area, you will first need to sign up with Google's Adwords program. If you don't have a Google Adwords account or if you want to find out more about Google Adwords, please see:
http://adwords.google.com/select/Login
Once you do this, follow relevant steps and remember Google shows ads based on relevancy and cost. So if you can't see your ad appearing then try raising your 'cost per click' or using an advertising message more specific to Gumtree content.