For embedded development on OSX, one can first install Xcode (including the command line utilities) and then MacPorts:
http://www.macports.orgMacPorts is a (FreeBSD ports-like) package manager with lots of tools available for download.
After that, searching for avr one just needs to do on the command line:
port search avr
And the result is:
avarice @2.13_1 (cross)
AVR JTAG-ICE control software
avr-binutils @2.24 (cross, devel)
FSF Binutils for avr cross development
avr-gcc @4.8.2 (cross, devel)
The GNU compiler collection for avr
avr-gdb @7.6.1 (cross)
GDB for the AVR processors
avr-libc @1.8.0 (cross)
C library for the AVR microcontroller.
avrdude @6.0.1 (cross, devel)
an Atmel AVR MCU programmer
simulavr @1.0.0_2 (emulators, devel)
Simulator for Atmel AVR microcontrollers
uisp @20050207 (devel)
AVR In-System Programmer
After that, to install avrdude (for instance) the command is only:
sudo port install avrdude
Warning: some embedded development tools like sdcc and gputils are not in the cross category of MacPorts.
After that, you are in command line paradise.
If you want something more "Graphical" check
http://embedxcode.weebly.com (Embedded development with Xcode as IDE).
My best regards
paf