I just posted this over
here, but thought it applied here too.
Sometimes, I think when people are designing logos, they get lost in the fact of portraying everything the application does.
Fortunately, you don't have to. That's what your iTunes app description is for.
What you want is a
globally recognised logo which symbolizes
you and your application
only.
The key to achieving this is simple. Complement colours, use fairly unique fonts, make stand out what you want to stand out, and most importantly, keep things simple.
Being in logo design for at least 3 years as a freelancer, I can't tell you the amount of stuff I have learnt just by watching other people and their experiences.
I've attached my web clip icon to give you a sense of the possible impact you need to create with your own logo.
Hope this helps.
R-Fly