Organising a group of people to work on a project can be complex, difficult, time-consuming - or you can just use Scrumy. There's no registration involved, just enter a project name and you're off.
Next, enter some "stories", high-level goals that you'd like to achieve. Then create a few to-do lists that will help you get there, and assign individual tasks to your friends and colleagues. They can then log on to see what's required, change the status of various tasks - set the first to "In Progress", say - and keep an eye on what's going on.

Scrumy is basic, but also simple to use and very effective. You have to be careful about what you put on your page, though - it's public and can be viewed by anyone who enters your URL. If that's a problem, check out Scrumy Pro, which adds password protection and a number of other useful extras for $7 a month.