Kim Burnim: What you want to look for are resources that are based on well-established principles of teaching and learning, which are referred to as best practices. Best practices for teaching young children include allowing children to learn new things in many different ways (such as through songs, books, art activities, puzzles, games, and other hands-on activities), making learning fun and playful, and lots of repetition.
Phonics instruction should be explicit rather than implicit. Implicit instruction relies on readers "discovering" clues about sound-spelling relationships; good readers can do this, but poor readers are not likely to do so. Explicit instruction is the most effective type of phonics instruction, especially for children at risk for reading difficulties.