You're in great shape to get started! If you want to expand (or free up your Macbook) from being wired to the DAC, you can use an Aiport Express as Ericjcabrera has suggested. I have been using iTunes to stream lossless datastreams to several AEs for the last year or so.
Although I was using the wireless capability of the AEs, I found that in my home, I was having problems with interference (microwave) and dropped connections (never could figure that out)!
This last weekend, I went ahead and hardwired my AEs to my network since which has totally eliminated any dropouts or disconnections due to wireless interference. So, I now have to patch up some drywall where I pulled network cabling, but the connections are rock solid.