Here are three ways you can get good copy for your website.

1. The easiest and most reliable way is to hire a professional copywriter. If you spend only one chunk of money on a website, this is where it should go. Rates vary widely, but you can expect to pay at least a couple thousand dollars for a good sales letter, one that will actually sell. Find a copywriter who understands direct-response, and preferably has experience with the web or with Internet marketing.
2. At least consider hiring a professional copywriter to critique the copy you write. This will usually cost much less than having him write copy from scratch. The final copy may also perform more poorly. However, depending on your skill level, a thorough critique could improve the performance of your copy 10% to 100%, or more. And in the process, you’ll also discover many techniques that professional copywriters use.
3. If you want to write your own copy, uncover the secrets of writing good copy. Go through David Garfinkel’s 12-week on-line multimedia course Killer Copy Tactics. Then keep up to date with Brian Clarke’s copyblogger and Michel Fortin’s blog. This will get you started. But remember, writing good copy is hard. Expect to have many failures before you succeed.

I myself use a combination of the above approaches. Over the span of years, I’ve put many hours personally into learning how to write. For experiments, where the goal is to judge whether there is general interest in an idea, my own copy does the trick. Similarly for blog entries or e-books. But for important pages and sales letters, I’ll work with a professional copywriter to critique the copy I write or to write copy from scratch.