plugin admin page to list posts by category

I want to create a plugin which, on its admin page under Manage can list all the posts for a selected category, much like Manage, Posts, does to which I want to add some stuff. Can I use existing WordPress functions or must I roll my own? Or is there a hook I could use to ad some extra options per post on the existing Manage Posts page – which will modify info in a separate table for the plugin.

Hope somebody will be kind enough to point me in the right direction – even if just pointing me at a decent plugin with this kind of functionality that i should study.

Thanx
A