My daughter is wants to write a book. How can she find information about publishers who may be interested in her story?

Every year a large book called the Writer's Market (2004 Writer's Market, 2005 Writer's Market, etc.) is published, which has a reasonably complete listing of book publishers and what they look for, along with submission guidelines and helpful hints for query letters, etc. That is the best resource to start with, and you should be able to get it in any big bookstore.

Rule of thumb, though: write first, then query. Don't bother querying before you have most or all of a good, complete draft done. Most publishers will want to see a complete story synopsis with one or two completed sample chapters. You can only get away with selling a book before you have written it after you have established a track record.

The best way to start is to self-publish. Great authors such as Stephen King and John Grisham started this way.

The following blog sites talk about authors and their books that got published:
http://myxlibris.blogspot.com/
http://www.iblogme.com/booklover/

This is going to sound a bit obvious, but the first place she needs to visit is a large bookshop, or selection of bookshops- she should look at who's publishing books that have a similar content and tone to her own- although bear in mind she would likely be turned down by a publisher who had published something too similar recently (for example, if a publisher has recently put out a romance set in Morocco, he'd be unlikely to take on another, even if the story itself were quite different). Certain publishers have very specific readerships, or only publish non-fiction, and it would be a waste of time to consider these if her story does not fit the criteria. Most publishers have websites which are worth a look for extra information, some even have sections aimed at aspiring authors.
She might also want to invest in an industry guide such as the annual Writers and Artists Yearbook (published by A&C Black Books) which will give lists of publishers, literary agents, competitions and also hints on how to present work to publishers and tips on how to improve your writing technically.
Bear in mind that few publishers will accept unsolicited manuscripts, and most insist on being approached by a literary agent, rather than directly by the author themselves (this is less true of smaller, independent publishers, so don't dismiss them, they may be your best hope)- the guide mentioned above can help her with this, or she may be able to find one via a local writers' group. When sending work to publishers you should always send an introductory letter first, briefly describing your story's content and asking if its ok for you to send part or all of the manuscript for consideration- never just send an unsolicited piece of work unless the publisher has specifically stated that they will accept them. Its likely to be returned unread.