There are times when the default unix tools installed on Mac OS X fall short. For instance, wget which is used to download files over the web using http, https, and ftp, is not available out-of-the-box.
Fink is one of several package managers available for Mac OS X that make it easy to download and install any number of software applications/tools.
To download Fink, you can head over here. I am running Leopard and as of today there is no binary release available, however, you can download the source files, and follow these instructions to build from source. There is a short description of how to use the Fink command line tools here.
After installation, I also recommend you run the following commands from a terminal, the first sets up the proper path information, the second retrieves the most current package descriptions:
> sudo fink selfupdate
Depending on the shell you are using you may also need to add . /sw/bin/init.sh to shell configuration file (e.g .bash_profile when using the bash shell) in your home directory so the path settings are correct each time you open a terminal. Note, there is a space character after the . in the above code above. To verify the path information is configured properly, close the current shell and re-open a new one, type in fink and you should see a listing of fink command options.
Here is how to get a list of available packages:
> fink list | more
To install a package, such as wget, try this:
> sudo fink install wget
If you like to tinker with various tools and applications, Fink will keep you occupied for some time.