What works so far?
Not much. You may have a chance to run many console apps, but right now, Darling is still something for hacking and not that much for using.
Isn't this violating Apple's EULA?
No, no part of this project contains code covered under Apple's EULA. As long as you are not using Darling to run something covered by Apple's EULA, you are not bound by it either. As a matter of fact, the aim is to avoid any APSL-licensed code too, just to be on the safe side. As of now, you can find several header files covered by the APSL (Apple's open source license) in the project source tree, but this is only temporary.
Why are you spending time dealing with apps that have better alternatives on Linux?
These applications turned to be good and simple enough for testing. You cannot build a complex project by focusing on something very complicated from the beginning. You have to start small and thing big.
When will it run XYZ?
Absolutely no idea, sorry.
Do you support other platforms such as *BSD or Windows?
Sorry, no. BSD may very well be possible, but Windows would take a lot of extra effort. Darling depends on lots of Linux specifics, which make the development easier.
Will you support applications for iPhone/iPod/iPad?
The intention is to support the ARM platform on the lowest levels (the dynamic loader an the Objective-C runtime). Rewriting the frameworks used on iOS is a whole different story, though.
Debunking Wine Myths is also an interesting read. Lots of explanations given there apply to Darling as well.