Objective-C 2 on GNUstep?

[Kevin Horton]

I'm working through an Objective-C 2 text to learn the language, and 
plan to eventually write a couple of small apps that I will use on iOS, 
OS X and GNUstep.  I'll do the serious app writing on OS X, but I hope 
to use a Linux netbook to work through the exercises in this text while 
travelling. But, I need a compiler and runtime for Linux that handles 
"Objective-C 2" features such as properties, etc

I've found a bit of general info on what I need to compile and run 
Objective-C code that uses some "Objective-C 2" features, but no 
specific info has leapt to my eye.  Is there any detailed info available 
on what I need to build, and how to build it, to be able to compile and 
run Objective-C 2 code on Linux - I'm running Ubuntu 10.04?

Thanks,
--

Kevin Horton
Ottawa, Canada