Ghost writing is more common than you probably think. Many a celebrity memoir has been ghost written by a 'jobbing' writer. Hunter Davies has written the 'autobiographies' of Wayne Rooney, Paul Gascoigne and John Prescott.
But, it's not just celebrities who need writers to write their words for them. If you think about it, everyone has a story to tell (just look at the true life magazines on the shelf every week). But not all of these people are good with words ... or writing them down and putting them into sentences that tell a compelling tale. Which is where the you, the ghost writer, come in.
Ghost writing is a business transaction. A writer offers their writing skills for payment. One of Lynne Hackles' first ghostwriting jobs was to write a love letter on behalf a friend. Her payment was a jam doughnut. Since then, Lynne's gone on to ghostwrite many other projects (this time for money), which she fits in around all of her other writing projects (short stories for magazines like Fiction Feast, columns for Writing Magazine, and many, many more).
It's possible to ghost write anything - a love letter, a best man's speech, an article, short story, autobiography, even a novel. If you would like to know more, I can recommend Lynne Hackles' book, Ghost writing. Here she tells how she began ghost writing, and demonstrates that many jobs are quite ordinary (just don't have your client hand over the cash in the window of a coffee shop, for all of your friends to see ... as Lynne once did. It gives a whole new meaning to 'services rendered'!). The book also has quotes from other ghost writers, each giving advice and tips for this line of work.
If you enjoy writing, and have never ghost written before, then Lynne's book will help lay down the groundwork, that many other ghosts have taken years to discover.