My kids have never not wanted to read. In fact sometimes I threaten they are banned from reading! Of course this only lasts for about 30 minutes, or until their chores are done!
One thing that spurs an extra long reading session, is when Captain's favorite magazine is delivered.
We have a kids magazine produced by our church. It costs about $10 for a year (delivered) arrives every month and he loves it!
If your child doesn't like to sit and read a long book (Captain's current book is 'Raising Dragons' by Bryan Davis) magazines can be a great way to kick it in to gear!