First, how old is your daughter and is she getting extra help through school?
While I don't think it hurts to try almost anything when learning to read, I think it's important to find the cause of the problem. If she's young, just reading books together every night could be enough. She might be sight word reader as opposed to being a phonics kid. If she's older, there's a lot of good basic skills programs, like reading recovery (I think that's what it's called) that can help her.
If she really has some learning problem, I don't think a phonics game is going to help.
OTH, it never hurts to practice sounds. You have to decide how much use you'll get out of it for the money. Will you sit down everyday and work on it or will you let her go through it herself?