What do I need to code on a jailbroken iOS device?
I think I've already got all of the programs that I need - Xcode 4.3 (and iOSOpenDev), the iOS 5 SDK, theos, ldid and dpkg.
The Cydia FAQ is probably the best source of information on this topic. See http://cydia.saurik.com/faq/developing.html. Here’s an excerpt:
Q: Where do I get started with developing for jailbroken iOS?
A: It helps to know something about developing for normal iOS. You might also check out the iPhone Dev Wiki.
The wiki it points to has several “Quick Start” articles: http://iphonedevwiki.net/index.php/Main_Page#Quick_start