There are a number of sales letter generation software packages on the market that can write sales letter for you. The most well know and probably the most popular is Sales Letter Generator which is marketed by the well known Web Entrepreneur Arman Morin. The benefit of this type of software is that it will save you time and you will get a good sales letter and small website out of the product. So you don't need so much copywriting experience.
You can check out the Sales Letter Generator Sales Page here