Hi Arachn1d, welcome! The first thing you should do is download the Bitcoin client on each computer. It will need to download the block chain, which might take an hour or so. In the meantime, explore the forums and find threads about mining. There are a few mining programs available, the only one I've used is the Python OpenCL Miner and that was with an nvidia card. You'll basically run the mining program, and point it at your running bitcoind client. You can do this with the CPU, GPU and GPU simultaneously, although the macbook will probably never generate any bitcoins. Ask in IRC if you need additional help:
http://webchat.freenode.net/?channels=#bitcoin-otc