Any good Apps?

in CCNA & CCENT
I was wondering if anyone has found any good apps to use to study for the ICND1 (and or 2)? I have an Iphone so Android apps won't be too helpful for me but feel free to post them for Android phone people who are also curious if their are any good ICND1 apps out there.
Comments
An app is great for the videos, etc. but it won't cover everything you need to do for preparation.
I used that and subnetting.net to really improve my subnetting speed.
Good Luck.
Jon
Thanks Thomas for the advice, I'll definitely look into it!