iTunes is a MP3 music application made by Apple, the creators of the Mac.
Polarbit is my favorite developer for the iPhone/iPod Touch. They made games like Raging Thunder, Wave Blazer, and Crash Bandicoot Nitro Kart 3D.
They are highly trusted.
Dizzy Bee is my favorite iPhone applications, made by the company Igloo Games. They also made the newer Dizzy Bee 2, which has "more levels, baddies, fruit firends, and fun."
This is a very good iPhone/Mac news website.
This website reviews iPhone applications on a scale of 1-4, one being "Avoid," two being "Caution," etc.