Git - Workflow

Hello,

I am relatively new to git and could use help understanding how to do this...

I want to pull a php framework from a public repo. From there I want to add a bunch of modules from other public repos.

How can I do this so that I can always keep the framework & the modules up to date? How can I easily pull updates for each? Is this possible?

Thanks.

I find this online book a good source for information.
2.5 Working with Remotes talks about working with multiple remote sites.