If you're working with colleagues or friends on a network and want to share your data with them, Fliq for Mac is a powerful and relatively easy way to do so.
The good thing is it's not limited to one file type - it can send and receive photos, contacts, notes, tasks and documents with others over a network. It also works for contacts and events and the great thing is it's integrated with all the major Mac apps. So for example, if you want to share contacts from your Address Book with co-workers you can and the same for tasks in iCal. Similarly, photos can be shared from iPhoto although not files in iMovie.
However, although it's easier from to share things from the above apps, it will accept any file simply by dragging and dropping them into the main Fliq interface. It's even designed to integrate with iPhones although you'll need Fliq for iPhone installed to do so.
Fliq is generally very easy to use and if you're collaborating on a project, it's a great way to share files and folders in case your office network isn't functioning as well as it should be.