You are looking for a "headshot", or "business portrait".  There are a few different characteristics that define the style, which I will touch on as I go.

**Focal length:**

The standard "portrait" focal length is about 85mm, but any short-telephoto will be ideal.  The idea is that you want to 1) Get a nice closeup of your subject, and 2) Use a telephoto, which unlike a normal or wide-angle lens, will provide "[background compression][1]".  Basically, this will make the image feel a little flatter, so you can avoid the really long nose look.

**Lighting:**

This depends on your subject, but usually, [Rembrandt Lighting][2] is a good option.

**Background:**

This is also dependent on your subject, but commonly, a dark, neutral  background will work well.  For some professions, such as an attorney, there is an expected background (bookshelves for instance), but most of the time, you want the background to be neutral and free from distractions.

**Crop:**

The standard look is a portrait layout (taller than wide), with the subject centered in the frame, and eye-level [placed on the top third mark][3].


  [1]: https://photo.stackexchange.com/questions/2548/what-is-background-compression
  [2]: https://photo.stackexchange.com/questions/6601/what-is-rembrandt-lighting-and-when-do-i-use-it
  [3]: https://photo.stackexchange.com/questions/521/what-is-the-rule-of-thirds