The Settings API, added in WordPress 2.7, allows admin pages containing settings forms to be managed semi-automatically. It lets you define settings pages, sections within those pages and fields within the sections.
New settings pages can be registered along with sections and fields inside them. Existing settings pages can also be added to by registering new settings sections or fields inside of them.
Organizing registration and validation of fields still requires some effort from developers using the Settings API, but avoids a lot of complex debugging of underlying options management.