At what reading level are your students? There are many websites that offer practice, especially at the beginning level. Below are some you can check out.
The best thing you can do is to provide time for reading. Let the students pick their own books, then provide time for them to read (20 minutes or so) and then to talk about what they have read. This will spark interest and motivate students to read more. Also, read to your students. Modeling is also motivating. That's free, too!
I agree with Barb K's resources. I would also add that, for young students and beginning readers PBS kids island (listed below) is great because it tracks the child's progress for you. I was on there today, and it appears that a similar site is in development for older children (launch date in April). In addition, pbskids has numerous pages devoted to reading via the shows: "Word World" (letter ID and sound, rhyme etc), "The Electric Co." (sight words, letter patterns/phonics) etc.
Free tutoring is available with eduwizards.com, where you can take free tutoring for 20 minutes. The tutoring is delivered by whiteboard software that allows you to do text, voice and video chat. I took many sessions when I was preparing for SAT... Other benefit is that you can read reviews for each tutor right away.
Having the The Academic Advantage for any student really is a great way of ensuring that the education they acquire will help them in the long run. The first thing you need to consider is the fact that a child's interest may be hard to get, but with the help of tactics and strategies, you can make learning more fun.