On the PC side of the computing world, there are many choices of video editing software on both the high and low end. On the Mac side, there isn't as wide a selection and since Adobe stopped making Premiere for the Mac, the choice for most people comes down to Final Cut Pro, Final Cut Express, iMovie or Avid Xpress DV. There are a few other higher-end packages, but they're usually out of the reach of independent producers.
If you're on a really tight budget, there are a few free Mac video editing choices you can explore.
* iMovie - Although the current version of iMovie is available as part of Apple's iLife software suite for a $79 charge, Apple has included a copy of iMovie with every Mac sold for a number of years. If your Mac is of recent vintage, you've likely already a copy of an earlier version of iMovie installed or on the software disks that came with the computer. Although previous versions may not have all the bells and whistles of the latest and greatest (such as support for HD editing), iMovie in any incarnation is very functional and has been used for cutting everything from documentaries to feature-length projects.
* HyperEngine AV - Although not quite as easy to use as iMovie, Arboretum Software's HyperEngine AV makes up for the slightly larger learning curve by being far more flexible. HyperEngine AV gives you more video and audio tracks than there are in iMovie as well as allowing you to add text and photos as well. It's available for free, so the price is right.
* Jahshaka - The open-source movement has contributed numerous specialty applications that are available for the asking. The Jahshaka project combines video editing with additional special effects tools that delivers a great deal of power and flexibility. It's these "extra" abilities that make the Jahshaka package attractive to someone who wants an integrated tool for production. It also includes workgroup features so a small studio can use it to collaborate. Again, it's a free solution and isn't just for Mac users either. Windows and various Unix versions available as well.
* Avid FreeDV - Avid is known for their high-end editing products but has tried to compete on the low-end as well. Avid FreeDV is a feature-limited edition of their Xpress family of products. With support for only two video and audio tracks, it's almost like iMovie with the Avid interface. Avid has released this free version in the hope that it will serve as a stepping stone to their $495 Xpress DV or $1695 Xpress Pro products. Comparing the feature list between the three makes one think perhapsraps they limited too many features to make this really useful, but it is an option. Also available for Windows.