MyOS by Steven Barker ($0.99)

MyOS is a control freaks dream come true. This handy tweak lets you turn off, and back on, features in your devices OS which can free up ram.

What you can turn off:

Homescreen wallpaper
Multitasking (turn this off if you use Backgrounder)
Camera
HDR (High Dynamic Range camera setting)
Appstore
Unified iPod
Contacts
Voice Control.

Install via Cydia

I gained ~15-24mb of ram after disabling native multitasking and voice control! (check your ram using SBSettings)

Cydia Store Link (iDevice only):
MyOS