A lot of comments here saying how Obj-C is "ugly", and so forth. I wonder how many commenters are actually using it to any great extent, on a day-to-day basis, rather than have just looked at it out of curiosity for five minutes?
If you want to write an app now, Obj-C is the only sensible choice. Swift looks promising, but it's not ready. It's changing almost weekly and at the moment it's actually introducing bugs into the frameworks where none exist in Obj-C. If you want to live on the bleeding edge, go for Swift, but if you want to write an app, get it working and ship it out of the door, Obj-C is the only game in town today.
Once you get into Obj-C, it's a much more elegant language than it's usually given credit for anyway. Sure, it's old, but the runtime and compiler work put in in recent years makes up for many of its older roots. Manual memory management is not required, there is a dot syntax for properties and so on, so square brackets are not the only way to call getter/setter methods. As a pure superset of C99, it's easy for a C programmer to learn. It's also a small language. The real power lies in the frameworks, and that will take you far longer to learn than the language. Don't be put off by the superficial "ugliness" of Obj-C code, it isn't relevant. It's expressive and straightforward, and as a former C++ programmer, I also found it dramatically more productive when I first adopted it over a decade ago. It is possible to become fond of it, believe it or not. Whether the same eventually becomes true of Swift, only time will tell. Ignore the nay-sayers who have probably never actually used Obj-C in anger in their lives.