Need reading game

Do any of you know of a game for the ipad or computer that teaches reading that would be good for a 4th grader?  My DD who is struggling to read (maybe reads end 1st grade/beginning 2nd grade level) has started to voice a desire to read.  We are going to have her tested by the school district this year and hopefully tutored by them, but I thought if there was a game for the ipad or computer that she could do in the meantime, that it would be good for her.