CoreAnimation is the foundation for creating high-performance and whimsical user interfaces, but is often overlooked by app developers. Starting with the high level view controller transitions and automatic view property animations, dive down into CALayer transforms, actions, and key framing. Whether you’re creating a line of business application or a game, your users will thank you for enhancing their UI.
CoreAnimation, and the level of things you can do with it, really show just how huge the iOS API's are. Frank's coverage is great, as usual. The video may be a bit off, tho - showing animations in a screen recorded format did work that well live, but there is a sample project which shows off all the stuff he covers.
And of course, if you want to know more about UIAccessability, my seminar from the start of the month is up, too.
LayerVault, which is a source control-like thing for Photoshop, have an article up about why the went with a flat design for LayerVault:
Well-loved products on the web share a similar design aesthetic, with roughly the same kinds of bevels, inset shadows, and drop shadows. For designers, achieving this level of “lickable” interface is a point of pride. For us, and for a minority of UI designers out there, it feels wrong.
I think both Android and Windows (Phone) 7/8 are good examples of the flat or flatter design style, and Mountain Lion is a lot flatter than older versions of OSX. It's a design style I quite like, but I think a part of it is that its based around typography and color, not gradients and subtle light effects - things which I can do in Photoshop and actually make look half decent.
The article links off to Big Human as an example of people who do nice flat design, specifically the Jetsetter app. If you have an iPhone, grab it down (it's free) - the animations and design of the app is really quite impressive.
Maybe I'm new to this one, but MediaLoot have loads of nice iOS templates for not a lot of money (usually about $10 each). They come with an iOS project (in Objective-C), but mostly use the UIAppearance API's, so they should be easy to implement in MonoTouch.
Also: whisper has it that Glyphish is about to
release, or has just released, a whole new icon pack. It's not on his
website yet, but I've bought them - for $25, it's an easy decision for
200 excellent new icons. Keep an eye out.