Semlin,
You'll be glad to know that I'm typing this from a Mac which I just used to download a package. There are only a few quick modifications that you need to make....
First off, you need to delete wget.exe from the zip package and replace it with this version for Macs:
http://www.statusq.org/images/wget.zip
Then, you need to rename begin_download.bat to begin_download.sh and open it in text edit. Then, goto edit->find and replace
all instances of "wget" with "./wget" and replace all instances of "cookies.txt" with "./cookies.txt"
Get the cookies using the firefox method, put it into cookies.txt (use textedit) SAVE IT and close stuff up. Open up a terminal, cd to your downloader directory, and type "./begin_download" and hit enter The magic should then happen
I'm not a mac user and don't know their ins-and-outs but I think those directions make sense. It is still unix-like at its core