The first question you need to ask yourself: Virtualization or dual-boot.
Virtualization - Fusion (VMWare)
or Parallels (Apple)
come to mind. Fusion is supposedly the better of the 2 if you want to run a *nix related OS. Possible downside: Both cost money.
Dual-boot - It is possible to dual boot osx and linux on mac-intel hardware. My Mac Pro runs LFS and OS-X in a dual boot configuration. It took a lot of searching and trying before I got it up and running (made an entry about it in the LFS group
here at LQ). Things have become a bit easier by now, but it is still a challenge. There's enough help on the internet if you want to try (feed google with dual boot mac mini linux
Hope this clears things up a bit.