My wife is a certified reading specialist and this is a question she runs into quite a bit. I'll attempt to "channel" for her for a moment.
1. Read to your child early and often.
Rebecka (another person who responded to the post) is completely right. But, don't stop when they can read for themselves. Keep reading to them as long as they'll let you.
2. Make reading accessible and interesting.
Try to make sure that your child has access to reading material that is on their reading level and of interest to them. My wife suggests a ten page rule. If your child doesn't like the book by the first ten pages, put it away and find something else to read. (The Scarlet Letter is a notable exception to this rule -- especially if you have to read it for school.) Public libraries often have very large selections of books for children and young adults on a variety of subjects. Most children can find an author or or genre they like after a few tries.
3. Don't be afraid of introducing your child to other formats.
I was not much of a reader until my mother started letting me buy comic books. (People who know me will tell you this was apparently a formative experience.) Once I loved the comic books, I started finding books in the library that were fantasy and science fiction. (Although, if you haven't read a comic book in the last few years, they've really changed and you should always pre-view them to make sure they are age appropriate.) Kids who are interested in sports may want to skim the sports section of the local newspaper. Kids who like humor may want to read the comics section.
4. Limit the time spent on electronic devices.
In our house we have a thirty minute limit on computers, video games, ipods, etc. We don't have specified limits on television, but it is something we try to minimize. We could probably do a better job of enforcing these limits. But the basic idea is that if kids are spending all their time pushing buttons, they'll be less likely to sit and read a book. Our kids had some books assigned to read over the summer by their school. We asked them to be sure and read at least a chapter out of the books before "plugging in". Another option is to require a minute of reading for every minute of electronic access. So, you have to read for thirty minutes before you play video games for thirty minutes.
5. Make reading portable.
You don't have to have a Kindle, Nook or iPod to take your reading with you. Have your children take books with them in the car or other situation where they will have to wait for something. (This assumes they can read in the car without getting carsick.)
6. Model good reading behaviors.
Read books yourself. Talk to your kids about what you're reading. When possible, read the books they are reading. Talk with them about the books you've read together. What did you like or dislike about the books? What happened that surprised you? What would you have done differently?
7. Realize that it may be slow going at first.
Younger readers will not be able to sit and read independently for long periods of time. Older children who haven't gotten used to reading may have to work up to reading for more than thirty minutes at a time. If there is some sort of reading problem or disability, try to have them break their reading into "chunks" so they won't be so frustrated.
What did your teachers and parents do to encourage you to read as a child?