If you are based in the UK and need to send money to Nigeria, Global Link might be a good option for you. With over 150 agents based in the UK (predominantly in London), Global Link ensures a team who really know their product - all employees are African.
You won't need a bank account or credit card to make a transfer, and money should arrive the same day (or at the latest next day).
On the downside front, Global Link charge fairly high commission fees and are vague on other fees, so you might find yourself forking out more than you had anticipated. There are no terms and conditions, so it is very wise to really make sure you know what is being offered - although Global Link do claim to recognise their risk exposure to money laundering and do keep a record of all transactions.