There are loads of free resources about this on GTD Times, our blog. For example:
I would suggest putting "project" into the search box of GTD Times and you'll see loads of helpful posts like this.
As for paid content, there is tons of educational content on GTD Connect about projects, including a webinar on project planning. The free trial will give you access to this content to play on the Connect site. (You just need to be a subscribing member to download.)
We also have an audio product coming out in November on the best practices of Managing Projects. That covers all of the common questions we get about projects.
Hope this helps!