My kids were always "eh" on Starfall and other websites we tried (can't remember if we tired the ones momoftwins listed), but they both loved the Clifford the Big Red Dog "Phonics" and "Reading" games for ages 4-6 on CD. And the Reader Rabbit ones, too. These are old-school so they're super cheap on Amazon or eBay.

You can get eBooks that read themselves if you have a ebook reader with sound. We have a Nook HD and I have several early reader books on there that DS likes to use.